Merge remote-tracking branch 'origin/master'

README.md

@@ -2,8 +2,9 @@
 
 # 30 seconds of code
 
-[![License](https://img.shields.io/badge/license-CC0--1.0-blue.svg)](https://github.com/30-seconds/30-seconds-of-code/blob/master/LICENSE) [![npm Downloads](https://img.shields.io/npm/dt/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![npm Version](https://img.shields.io/npm/v/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.com/30-seconds/30-seconds-of-code.svg?branch=master)](https://travis-ci.com/30-seconds/30-seconds-of-code) [![Codacy Badge](https://api.codacy.com/project/badge/Grade/6ab7791fb1ea40b4a576d658fb96807f)](https://www.codacy.com/app/Chalarangelo/30-seconds-of-code?utm_source=github.com&utm_medium=referral&utm_content=30-seconds/30-seconds-of-code&utm_campaign=Badge_Grade) [![Maintainability](https://api.codeclimate.com/v1/badges/4b8c1e099135f2d53413/maintainability)](https://codeclimate.com/github/30-seconds/30-seconds-of-code/maintainability) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) [![Known Vulnerabilities](https://snyk.io/test/github/30-seconds/30-seconds-of-code/badge.svg?targetFile=package.json)](https://snyk.io/test/github/30-seconds/30-seconds-of-code?targetFile=package.json) [![ProductHunt](https://img.shields.io/badge/producthunt-vote-orange.svg)](https://www.producthunt.com/posts/30-seconds-of-code)
+> *This README is built using [markdown-builder](https://github.com/30-seconds/markdown-builder).*
 
+[![License](https://img.shields.io/badge/license-CC0--1.0-blue.svg)](https://github.com/30-seconds/30-seconds-of-code/blob/master/LICENSE) [![npm Downloads](https://img.shields.io/npm/dt/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![npm Version](https://img.shields.io/npm/v/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.com/30-seconds/30-seconds-of-code.svg?branch=master)](https://travis-ci.com/30-seconds/30-seconds-of-code) [![Codacy Badge](https://api.codacy.com/project/badge/Grade/6ab7791fb1ea40b4a576d658fb96807f)](https://www.codacy.com/app/Chalarangelo/30-seconds-of-code?utm_source=github.com&utm_medium=referral&utm_content=30-seconds/30-seconds-of-code&utm_campaign=Badge_Grade) [![Maintainability](https://api.codeclimate.com/v1/badges/4b8c1e099135f2d53413/maintainability)](https://codeclimate.com/github/30-seconds/30-seconds-of-code/maintainability) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) [![Known Vulnerabilities](https://snyk.io/test/github/30-seconds/30-seconds-of-code/badge.svg?targetFile=package.json)](https://snyk.io/test/github/30-seconds/30-seconds-of-code?targetFile=package.json) [![ProductHunt](https://img.shields.io/badge/producthunt-vote-orange.svg)](https://www.producthunt.com/posts/30-seconds-of-code)
 
 > Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 

dist/NOTICE.md

@@ -1,15 +0,0 @@
-# WARNING!
-
-The `_30s` module is not production ready. Do NOT use it in production websites.
-It is strictly for testing purposes at this moment in time. Snippets do not have
-any unit tests written and will not be reliable.
-
-Snippet names can and will change without notice between minor versions.
-
-Given the version `0.x.y`:
-
-* `x` indicates a snippet name change.
-* `y` indicates a new snippet or fix.
-
-If your project is not serious and you do not care about the above issues, you will want
-to use the `es5` version and also include `babel-polyfill` for widest browser support.

dist/_30s.es5.js

@@ -223,7 +223,7 @@
   };
 
   var atob = function atob(str) {
-    return new Buffer(str, 'base64').toString('binary');
+    return Buffer.from(str, 'base64').toString('binary');
   };
 
   var attempt = function attempt(fn) {
@@ -328,7 +328,7 @@
   };
 
   var btoa = function btoa(str) {
-    return new Buffer(str, 'binary').toString('base64');
+    return Buffer.from(str, 'binary').toString('base64');
   };
 
   var byteSize = function byteSize(str) {
@@ -1007,6 +1007,16 @@
     return (dateFinal - dateInitial) / (1000 * 3600 * 24);
   };
 
+  var getImages = function getImages(el) {
+    var includeDuplicates = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
+
+    var images = _toConsumableArray(el.getElementsByTagName('img')).map(function (img) {
+      return img.getAttribute('src');
+    });
+
+    return includeDuplicates ? images : _toConsumableArray(new Set(images));
+  };
+
   var getMeridiemSuffixOfInteger = function getMeridiemSuffixOfInteger(num) {
     return num === 0 || num === 24 ? 12 + 'am' : num === 12 ? 12 + 'pm' : num < 12 ? num % 12 + 'am' : num % 12 + 'pm';
   };
@@ -1309,6 +1319,10 @@
     return dividend % divisor === 0;
   };
 
+  var isDuplexStream = function isDuplexStream(val) {
+    return val !== null && _typeof(val) === 'object' && typeof val.pipe === 'function' && typeof val._read === 'function' && _typeof(val._readableState) === 'object' && typeof val._write === 'function' && _typeof(val._writableState) === 'object';
+  };
+
   var isEmpty = function isEmpty(val) {
     return val == null || !(Object.keys(val) || val).length;
   };
@@ -1367,6 +1381,10 @@
     return obj !== null && (_typeof(obj) === 'object' || typeof obj === 'function') && typeof obj.then === 'function';
   };
 
+  var isReadableStream = function isReadableStream(val) {
+    return val !== null && _typeof(val) === 'object' && typeof val.pipe === 'function' && typeof val._read === 'function' && _typeof(val._readableState) === 'object';
+  };
+
   var isSameDate = function isSameDate(dateA, dateB) {
     return dateA.toISOString() === dateB.toISOString();
   };
@@ -1402,6 +1420,10 @@
     }
   };
 
+  var isStream = function isStream(val) {
+    return val !== null && _typeof(val) === 'object' && typeof val.pipe === 'function';
+  };
+
   var isString = function isString(val) {
     return typeof val === 'string';
   };
@@ -1431,6 +1453,10 @@
     }
   };
 
+  var isWritableStream = function isWritableStream(val) {
+    return val !== null && _typeof(val) === 'object' && typeof val.pipe === 'function' && typeof val._write === 'function' && _typeof(val._writableState) === 'object';
+  };
+
   var join = function join(arr) {
     var separator = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : ',';
     var end = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : separator;
@@ -2493,31 +2519,9 @@
   };
 
   var takeRightWhile = function takeRightWhile(arr, func) {
-    var _iteratorNormalCompletion = true;
+    return arr.reduceRight(function (acc, el) {
-    var _didIteratorError = false;
+      return func(el) ? acc : [el].concat(_toConsumableArray(acc));
-    var _iteratorError = undefined;
+    }, []);
-
-    try {
-      for (var _iterator = arr.reverse().keys()[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
-        var i = _step.value;
-        if (func(arr[i])) return arr.reverse().slice(arr.length - i, arr.length);
-      }
-    } catch (err) {
-      _didIteratorError = true;
-      _iteratorError = err;
-    } finally {
-      try {
-        if (!_iteratorNormalCompletion && _iterator.return != null) {
-          _iterator.return();
-        }
-      } finally {
-        if (_didIteratorError) {
-          throw _iteratorError;
-        }
-      }
-    }
-
-    return arr;
   };
 
   var takeWhile = function takeWhile(arr, func) {
@@ -2655,8 +2659,7 @@
     }, acc);
   };
 
-  var triggerEvent = function triggerEvent(el, eventType) {
+  var triggerEvent = function triggerEvent(el, eventType, detail) {
-    var detail = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : undefined;
     return el.dispatchEvent(new CustomEvent(eventType, {
       detail: detail
     }));
@@ -3005,6 +3008,7 @@
   exports.get = get;
   exports.getColonTimeFromDate = getColonTimeFromDate;
   exports.getDaysDiffBetweenDates = getDaysDiffBetweenDates;
+  exports.getImages = getImages;
   exports.getMeridiemSuffixOfInteger = getMeridiemSuffixOfInteger;
   exports.getScrollPosition = getScrollPosition;
   exports.getStyle = getStyle;
@@ -3048,6 +3052,7 @@
   exports.isBrowser = isBrowser;
   exports.isBrowserTabFocused = isBrowserTabFocused;
   exports.isDivisible = isDivisible;
+  exports.isDuplexStream = isDuplexStream;
   exports.isEmpty = isEmpty;
   exports.isEven = isEven;
   exports.isFunction = isFunction;
@@ -3061,14 +3066,17 @@
   exports.isPrime = isPrime;
   exports.isPrimitive = isPrimitive;
   exports.isPromiseLike = isPromiseLike;
+  exports.isReadableStream = isReadableStream;
   exports.isSameDate = isSameDate;
   exports.isSorted = isSorted;
+  exports.isStream = isStream;
   exports.isString = isString;
   exports.isSymbol = isSymbol;
   exports.isTravisCI = isTravisCI;
   exports.isUndefined = isUndefined;
   exports.isUpperCase = isUpperCase;
   exports.isValidJSON = isValidJSON;
+  exports.isWritableStream = isWritableStream;
   exports.join = join;
   exports.last = last;
   exports.lcm = lcm;

dist/_30s.esm.js

@@ -72,7 +72,7 @@ const arrayToHtmlList = (arr, listID) =>
 
 const ary = (fn, n) => (...args) => fn(...args.slice(0, n));
 
-const atob = str => new Buffer(str, 'base64').toString('binary');
+const atob = str => Buffer.from(str, 'base64').toString('binary');
 
 const attempt = (fn, ...args) => {
   try {
@@ -124,7 +124,7 @@ const bottomVisible = () =>
   document.documentElement.clientHeight + window.scrollY >=
   (document.documentElement.scrollHeight || document.documentElement.clientHeight);
 
-const btoa = str => new Buffer(str, 'binary').toString('base64');
+const btoa = str => Buffer.from(str, 'binary').toString('base64');
 
 const byteSize = str => new Blob([str]).size;
 
@@ -509,6 +509,11 @@ const getColonTimeFromDate = date => date.toTimeString().slice(0, 8);
 const getDaysDiffBetweenDates = (dateInitial, dateFinal) =>
   (dateFinal - dateInitial) / (1000 * 3600 * 24);
 
+const getImages = (el, includeDuplicates = false) => {
+  const images = [...el.getElementsByTagName('img')].map(img => img.getAttribute('src'));
+  return includeDuplicates ? images : [...new Set(images)];
+};
+
 const getMeridiemSuffixOfInteger = num =>
   num === 0 || num === 24
     ? 12 + 'am'
@@ -704,6 +709,15 @@ const isBrowserTabFocused = () => !document.hidden;
 
 const isDivisible = (dividend, divisor) => dividend % divisor === 0;
 
+const isDuplexStream = val =>
+  val !== null &&
+  typeof val === 'object' &&
+  typeof val.pipe === 'function' &&
+  typeof val._read === 'function' &&
+  typeof val._readableState === 'object' &&
+  typeof val._write === 'function' &&
+  typeof val._writableState === 'object';
+
 const isEmpty = val => val == null || !(Object.keys(val) || val).length;
 
 const isEven = num => num % 2 === 0;
@@ -737,6 +751,13 @@ const isPromiseLike = obj =>
   (typeof obj === 'object' || typeof obj === 'function') &&
   typeof obj.then === 'function';
 
+const isReadableStream = val =>
+  val !== null &&
+  typeof val === 'object' &&
+  typeof val.pipe === 'function' &&
+  typeof val._read === 'function' &&
+  typeof val._readableState === 'object';
+
 const isSameDate = (dateA, dateB) => dateA.toISOString() === dateB.toISOString();
 
 const isSorted = arr => {
@@ -748,6 +769,8 @@ const isSorted = arr => {
   }
 };
 
+const isStream = val => val !== null && typeof val === 'object' && typeof val.pipe === 'function';
+
 const isString = val => typeof val === 'string';
 
 const isSymbol = val => typeof val === 'symbol';
@@ -767,6 +790,13 @@ const isValidJSON = obj => {
   }
 };
 
+const isWritableStream = val =>
+  val !== null &&
+  typeof val === 'object' &&
+  typeof val.pipe === 'function' &&
+  typeof val._write === 'function' &&
+  typeof val._writableState === 'object';
+
 const join = (arr, separator = ',', end = separator) =>
   arr.reduce(
     (acc, val, i) =>
@@ -1385,11 +1415,8 @@ const take = (arr, n = 1) => arr.slice(0, n);
 
 const takeRight = (arr, n = 1) => arr.slice(arr.length - n, arr.length);
 
-const takeRightWhile = (arr, func) => {
+const takeRightWhile = (arr, func) =>
-  for (let i of arr.reverse().keys())
+  arr.reduceRight((acc, el) => (func(el) ? acc : [el, ...acc]), []);
-    if (func(arr[i])) return arr.reverse().slice(arr.length - i, arr.length);
-  return arr;
-};
 
 const takeWhile = (arr, func) => {
   for (const [i, val] of arr.entries()) if (func(val)) return arr.slice(0, i);
@@ -1492,8 +1519,8 @@ const tomorrow = (long = false) => {
 
 const transform = (obj, fn, acc) => Object.keys(obj).reduce((a, k) => fn(a, obj[k], k, obj), acc);
 
-const triggerEvent = (el, eventType, detail = undefined) =>
+const triggerEvent = (el, eventType, detail) =>
-  el.dispatchEvent(new CustomEvent(eventType, { detail: detail }));
+  el.dispatchEvent(new CustomEvent(eventType, { detail }));
 
 const truncateString = (str, num) =>
   str.length > num ? str.slice(0, num > 3 ? num - 3 : num) + '...' : str;
@@ -1624,4 +1651,4 @@ const zipWith = (...array) => {
   );
 };
 
-export { CSVToArray, CSVToJSON, JSONToFile, JSONtoCSV, RGBToHex, URLJoin, UUIDGeneratorBrowser, UUIDGeneratorNode, all, allEqual, any, approximatelyEqual, arrayToCSV, arrayToHtmlList, ary, atob, attempt, average, averageBy, bifurcate, bifurcateBy, bind, bindAll, bindKey, binomialCoefficient, bottomVisible, btoa, byteSize, call, capitalize, capitalizeEveryWord, castArray, chainAsync, chunk, clampNumber, cloneRegExp, coalesce, coalesceFactory, collectInto, colorize, compact, compose, composeRight, converge, copyToClipboard, countBy, countOccurrences, counter, createElement, createEventHub, currentURL, curry, dayOfYear, debounce, decapitalize, deepClone, deepFlatten, deepFreeze, defaults, defer, degreesToRads, delay, detectDeviceType, difference, differenceBy, differenceWith, dig, digitize, distance, drop, dropRight, dropRightWhile, dropWhile, elementContains, elementIsVisibleInViewport, elo, equals, escapeHTML, escapeRegExp, everyNth, extendHex, factorial, fibonacci, filterNonUnique, filterNonUniqueBy, findKey, findLast, findLastIndex, findLastKey, flatten, flattenObject, flip, forEachRight, forOwn, forOwnRight, formatDuration, fromCamelCase, functionName, functions, gcd, geometricProgression, get, getColonTimeFromDate, getDaysDiffBetweenDates, getMeridiemSuffixOfInteger, getScrollPosition, getStyle, getType, getURLParameters, groupBy, hammingDistance, hasClass, hasFlags, hashBrowser, hashNode, head, hexToRGB, hide, httpGet, httpPost, httpsRedirect, hz, inRange, indentString, indexOfAll, initial, initialize2DArray, initializeArrayWithRange, initializeArrayWithRangeRight, initializeArrayWithValues, initializeNDArray, insertAfter, insertBefore, intersection, intersectionBy, intersectionWith, invertKeyValues, is, isAbsoluteURL, isAfterDate, isAnagram, isArrayLike, isBeforeDate, isBoolean, isBrowser, isBrowserTabFocused, isDivisible, isEmpty, isEven, isFunction, isLowerCase, isNil, isNull, isNumber, isObject, isObjectLike, isPlainObject, isPrime, isPrimitive, isPromiseLike, isSameDate, isSorted, isString, isSymbol, isTravisCI, isUndefined, isUpperCase, isValidJSON, join, last, lcm, longestItem, lowercaseKeys, luhnCheck, mapKeys, mapObject, mapString, mapValues, mask, matches, matchesWith, maxBy, maxDate, maxN, median, memoize, merge, minBy, minDate, minN, mostPerformant, negate, nest, nodeListToArray, none, nthArg, nthElement, objectFromPairs, objectToPairs, observeMutations, off, offset, omit, omitBy, on, onUserInputChange, once, orderBy, over, overArgs, pad, palindrome, parseCookie, partial, partialRight, partition, percentile, permutations, pick, pickBy, pipeAsyncFunctions, pipeFunctions, pluralize, powerset, prefix, prettyBytes, primes, promisify, pull, pullAtIndex, pullAtValue, pullBy, radsToDegrees, randomHexColorCode, randomIntArrayInRange, randomIntegerInRange, randomNumberInRange, readFileLines, rearg, recordAnimationFrames, redirect, reduceSuccessive, reduceWhich, reducedFilter, reject, remove, removeNonASCII, renameKeys, reverseString, round, runAsync, runPromisesInSeries, sample, sampleSize, scrollToTop, sdbm, serializeCookie, setStyle, shallowClone, shank, show, shuffle, similarity, size, sleep, smoothScroll, sortCharactersInString, sortedIndex, sortedIndexBy, sortedLastIndex, sortedLastIndexBy, splitLines, spreadOver, stableSort, standardDeviation, stringPermutations, stripHTMLTags, sum, sumBy, sumPower, symmetricDifference, symmetricDifferenceBy, symmetricDifferenceWith, tail, take, takeRight, takeRightWhile, takeWhile, throttle, timeTaken, times, toCamelCase, toCurrency, toDecimalMark, toHash, toKebabCase, toOrdinalSuffix, toSafeInteger, toSnakeCase, toggleClass, tomorrow, transform, triggerEvent, truncateString, truthCheckCollection, unary, uncurry, unescapeHTML, unflattenObject, unfold, union, unionBy, unionWith, uniqueElements, uniqueElementsBy, uniqueElementsByRight, uniqueSymmetricDifference, untildify, unzip, unzipWith, validateNumber, when, without, words, xProd, yesNo, zip, zipObject, zipWith };
+export { CSVToArray, CSVToJSON, JSONToFile, JSONtoCSV, RGBToHex, URLJoin, UUIDGeneratorBrowser, UUIDGeneratorNode, all, allEqual, any, approximatelyEqual, arrayToCSV, arrayToHtmlList, ary, atob, attempt, average, averageBy, bifurcate, bifurcateBy, bind, bindAll, bindKey, binomialCoefficient, bottomVisible, btoa, byteSize, call, capitalize, capitalizeEveryWord, castArray, chainAsync, chunk, clampNumber, cloneRegExp, coalesce, coalesceFactory, collectInto, colorize, compact, compose, composeRight, converge, copyToClipboard, countBy, countOccurrences, counter, createElement, createEventHub, currentURL, curry, dayOfYear, debounce, decapitalize, deepClone, deepFlatten, deepFreeze, defaults, defer, degreesToRads, delay, detectDeviceType, difference, differenceBy, differenceWith, dig, digitize, distance, drop, dropRight, dropRightWhile, dropWhile, elementContains, elementIsVisibleInViewport, elo, equals, escapeHTML, escapeRegExp, everyNth, extendHex, factorial, fibonacci, filterNonUnique, filterNonUniqueBy, findKey, findLast, findLastIndex, findLastKey, flatten, flattenObject, flip, forEachRight, forOwn, forOwnRight, formatDuration, fromCamelCase, functionName, functions, gcd, geometricProgression, get, getColonTimeFromDate, getDaysDiffBetweenDates, getImages, getMeridiemSuffixOfInteger, getScrollPosition, getStyle, getType, getURLParameters, groupBy, hammingDistance, hasClass, hasFlags, hashBrowser, hashNode, head, hexToRGB, hide, httpGet, httpPost, httpsRedirect, hz, inRange, indentString, indexOfAll, initial, initialize2DArray, initializeArrayWithRange, initializeArrayWithRangeRight, initializeArrayWithValues, initializeNDArray, insertAfter, insertBefore, intersection, intersectionBy, intersectionWith, invertKeyValues, is, isAbsoluteURL, isAfterDate, isAnagram, isArrayLike, isBeforeDate, isBoolean, isBrowser, isBrowserTabFocused, isDivisible, isDuplexStream, isEmpty, isEven, isFunction, isLowerCase, isNil, isNull, isNumber, isObject, isObjectLike, isPlainObject, isPrime, isPrimitive, isPromiseLike, isReadableStream, isSameDate, isSorted, isStream, isString, isSymbol, isTravisCI, isUndefined, isUpperCase, isValidJSON, isWritableStream, join, last, lcm, longestItem, lowercaseKeys, luhnCheck, mapKeys, mapObject, mapString, mapValues, mask, matches, matchesWith, maxBy, maxDate, maxN, median, memoize, merge, minBy, minDate, minN, mostPerformant, negate, nest, nodeListToArray, none, nthArg, nthElement, objectFromPairs, objectToPairs, observeMutations, off, offset, omit, omitBy, on, onUserInputChange, once, orderBy, over, overArgs, pad, palindrome, parseCookie, partial, partialRight, partition, percentile, permutations, pick, pickBy, pipeAsyncFunctions, pipeFunctions, pluralize, powerset, prefix, prettyBytes, primes, promisify, pull, pullAtIndex, pullAtValue, pullBy, radsToDegrees, randomHexColorCode, randomIntArrayInRange, randomIntegerInRange, randomNumberInRange, readFileLines, rearg, recordAnimationFrames, redirect, reduceSuccessive, reduceWhich, reducedFilter, reject, remove, removeNonASCII, renameKeys, reverseString, round, runAsync, runPromisesInSeries, sample, sampleSize, scrollToTop, sdbm, serializeCookie, setStyle, shallowClone, shank, show, shuffle, similarity, size, sleep, smoothScroll, sortCharactersInString, sortedIndex, sortedIndexBy, sortedLastIndex, sortedLastIndexBy, splitLines, spreadOver, stableSort, standardDeviation, stringPermutations, stripHTMLTags, sum, sumBy, sumPower, symmetricDifference, symmetricDifferenceBy, symmetricDifferenceWith, tail, take, takeRight, takeRightWhile, takeWhile, throttle, timeTaken, times, toCamelCase, toCurrency, toDecimalMark, toHash, toKebabCase, toOrdinalSuffix, toSafeInteger, toSnakeCase, toggleClass, tomorrow, transform, triggerEvent, truncateString, truthCheckCollection, unary, uncurry, unescapeHTML, unflattenObject, unfold, union, unionBy, unionWith, uniqueElements, uniqueElementsBy, uniqueElementsByRight, uniqueSymmetricDifference, untildify, unzip, unzipWith, validateNumber, when, without, words, xProd, yesNo, zip, zipObject, zipWith };

dist/_30s.js

@@ -78,7 +78,7 @@
 
   const ary = (fn, n) => (...args) => fn(...args.slice(0, n));
 
-  const atob = str => new Buffer(str, 'base64').toString('binary');
+  const atob = str => Buffer.from(str, 'base64').toString('binary');
 
   const attempt = (fn, ...args) => {
     try {
@@ -130,7 +130,7 @@
     document.documentElement.clientHeight + window.scrollY >=
     (document.documentElement.scrollHeight || document.documentElement.clientHeight);
 
-  const btoa = str => new Buffer(str, 'binary').toString('base64');
+  const btoa = str => Buffer.from(str, 'binary').toString('base64');
 
   const byteSize = str => new Blob([str]).size;
 
@@ -515,6 +515,11 @@
   const getDaysDiffBetweenDates = (dateInitial, dateFinal) =>
     (dateFinal - dateInitial) / (1000 * 3600 * 24);
 
+  const getImages = (el, includeDuplicates = false) => {
+    const images = [...el.getElementsByTagName('img')].map(img => img.getAttribute('src'));
+    return includeDuplicates ? images : [...new Set(images)];
+  };
+
   const getMeridiemSuffixOfInteger = num =>
     num === 0 || num === 24
       ? 12 + 'am'
@@ -710,6 +715,15 @@
 
   const isDivisible = (dividend, divisor) => dividend % divisor === 0;
 
+  const isDuplexStream = val =>
+    val !== null &&
+    typeof val === 'object' &&
+    typeof val.pipe === 'function' &&
+    typeof val._read === 'function' &&
+    typeof val._readableState === 'object' &&
+    typeof val._write === 'function' &&
+    typeof val._writableState === 'object';
+
   const isEmpty = val => val == null || !(Object.keys(val) || val).length;
 
   const isEven = num => num % 2 === 0;
@@ -743,6 +757,13 @@
     (typeof obj === 'object' || typeof obj === 'function') &&
     typeof obj.then === 'function';
 
+  const isReadableStream = val =>
+    val !== null &&
+    typeof val === 'object' &&
+    typeof val.pipe === 'function' &&
+    typeof val._read === 'function' &&
+    typeof val._readableState === 'object';
+
   const isSameDate = (dateA, dateB) => dateA.toISOString() === dateB.toISOString();
 
   const isSorted = arr => {
@@ -754,6 +775,8 @@
     }
   };
 
+  const isStream = val => val !== null && typeof val === 'object' && typeof val.pipe === 'function';
+
   const isString = val => typeof val === 'string';
 
   const isSymbol = val => typeof val === 'symbol';
@@ -773,6 +796,13 @@
     }
   };
 
+  const isWritableStream = val =>
+    val !== null &&
+    typeof val === 'object' &&
+    typeof val.pipe === 'function' &&
+    typeof val._write === 'function' &&
+    typeof val._writableState === 'object';
+
   const join = (arr, separator = ',', end = separator) =>
     arr.reduce(
       (acc, val, i) =>
@@ -1391,11 +1421,8 @@
 
   const takeRight = (arr, n = 1) => arr.slice(arr.length - n, arr.length);
 
-  const takeRightWhile = (arr, func) => {
+  const takeRightWhile = (arr, func) =>
-    for (let i of arr.reverse().keys())
+    arr.reduceRight((acc, el) => (func(el) ? acc : [el, ...acc]), []);
-      if (func(arr[i])) return arr.reverse().slice(arr.length - i, arr.length);
-    return arr;
-  };
 
   const takeWhile = (arr, func) => {
     for (const [i, val] of arr.entries()) if (func(val)) return arr.slice(0, i);
@@ -1498,8 +1525,8 @@
 
   const transform = (obj, fn, acc) => Object.keys(obj).reduce((a, k) => fn(a, obj[k], k, obj), acc);
 
-  const triggerEvent = (el, eventType, detail = undefined) =>
+  const triggerEvent = (el, eventType, detail) =>
-    el.dispatchEvent(new CustomEvent(eventType, { detail: detail }));
+    el.dispatchEvent(new CustomEvent(eventType, { detail }));
 
   const truncateString = (str, num) =>
     str.length > num ? str.slice(0, num > 3 ? num - 3 : num) + '...' : str;
@@ -1734,6 +1761,7 @@
   exports.get = get;
   exports.getColonTimeFromDate = getColonTimeFromDate;
   exports.getDaysDiffBetweenDates = getDaysDiffBetweenDates;
+  exports.getImages = getImages;
   exports.getMeridiemSuffixOfInteger = getMeridiemSuffixOfInteger;
   exports.getScrollPosition = getScrollPosition;
   exports.getStyle = getStyle;
@@ -1777,6 +1805,7 @@
   exports.isBrowser = isBrowser;
   exports.isBrowserTabFocused = isBrowserTabFocused;
   exports.isDivisible = isDivisible;
+  exports.isDuplexStream = isDuplexStream;
   exports.isEmpty = isEmpty;
   exports.isEven = isEven;
   exports.isFunction = isFunction;
@@ -1790,14 +1819,17 @@
   exports.isPrime = isPrime;
   exports.isPrimitive = isPrimitive;
   exports.isPromiseLike = isPromiseLike;
+  exports.isReadableStream = isReadableStream;
   exports.isSameDate = isSameDate;
   exports.isSorted = isSorted;
+  exports.isStream = isStream;
   exports.isString = isString;
   exports.isSymbol = isSymbol;
   exports.isTravisCI = isTravisCI;
   exports.isUndefined = isUndefined;
   exports.isUpperCase = isUpperCase;
   exports.isValidJSON = isValidJSON;
+  exports.isWritableStream = isWritableStream;
   exports.join = join;
   exports.last = last;
   exports.lcm = lcm;

snippet_data/snippets.json

@@ -2031,6 +2031,26 @@
         "hash": "baeec5f4220f1e457b11034e29d84277dbdc9fc5c9e69c1a225bb22f13b843ec"
       }
     },
+    {
+      "id": "getImages",
+      "type": "snippet",
+      "attributes": {
+        "fileName": "getImages.md",
+        "text": "Fetches all images from within an element and puts them into an array\n\nUse `Element.prototype.getElementsByTagName()` to fetch all `<img>` elements inside the provided element, `Array.prototype.map()` to map every `src` attribute of their respective `<img>` element, then create a `Set` to eliminate duplicates and return the array.",
+        "codeBlocks": [
+          "const getImages = (el, includeDuplicates = false) => {\n  const images = [...el.getElementsByTagName('img')].map(img => img.getAttribute('src'));\n  return includeDuplicates ? images : [...new Set(images)];\n};",
+          "getImages(document, true); // ['image1.jpg', 'image2.png', 'image1.png', '...']\ngetImages(document, false); // ['image1.jpg', 'image2.png', '...']"
+        ],
+        "tags": [
+          "browser",
+          "beginner"
+        ]
+      },
+      "meta": {
+        "archived": false,
+        "hash": "0f2ba02c6de1e9396abbef584139bea4dc379a6d465f4bebb151ad3b0f77ff6f"
+      }
+    },
     {
       "id": "getMeridiemSuffixOfInteger",
       "type": "snippet",

snippet_data/snippetsArchive.json

@@ -119,6 +119,23 @@
         "hash": "9de50bed5b8c247176570f743c8154a5ec4093432f8a09ba91c423d78af47169"
       }
     },
+    {
+      "id": "heronArea",
+      "type": "snippet",
+      "attributes": {
+        "fileName": "heronArea.md",
+        "text": "Returns the area of a triangle using only the 3 side lengths, Heron's formula. Assumes that the sides define a valid triangle. Does NOT assume it is a right triangle.\n\nMore information on what Heron's formula is and why it works available here: https://en.wikipedia.org/wiki/Heron%27s_formula.\n\nUses `Math.sqrt()` to find the square root of a value.",
+        "codeBlocks": [
+          "const heronArea = (side_a, side_b, side_c) => {\n    const p = (side_a + side_b + side_c) / 2\n    return Math.sqrt(p * (p-side_a) * (p-side_b) * (p-side_c))\n  };",
+          "heronArea(3, 4, 5); // 6"
+        ],
+        "tags": []
+      },
+      "meta": {
+        "archived": true,
+        "hash": "594721a84a8fe31c32482e9f475f5126b7cf499462d9408b3cfaee2021a96a30"
+      }
+    },
     {
       "id": "howManyTimes",
       "type": "snippet",
@@ -297,8 +314,10 @@
           "fibonacciCountUntilNum(10); // 7",
           "const fibonacciUntilNum = num => {\n  let n = Math.ceil(Math.log(num * Math.sqrt(5) + 1 / 2) / Math.log((Math.sqrt(5) + 1) / 2));\n  return Array.from({ length: n }).reduce(\n    (acc, val, i) => acc.concat(i > 1 ? acc[i - 1] + acc[i - 2] : i),\n    []\n  );\n};",
           "fibonacciUntilNum(10); // [ 0, 1, 1, 2, 3, 5, 8 ]",
-          "const howManyTimes = (num, divisor) => {\n  if (divisor === 1 || divisor === -1) return Infinity;\n  if (divisor === 0) return 0;\n  let i = 0;\n  while (Number.isInteger(num / divisor)) {\n    i++;\n    num = num / divisor;\n  }\n  return i;\n};",
+          "const heronArea = (side_a, side_b, side_c) => {\n    const p = (side_a + side_b + side_c) / 2\n    return Math.sqrt(p * (p-side_a) * (p-side_b) * (p-side_c))\n  };",
-          "howManyTimes(100, 2); // 2\nhowManyTimes(100, 2.5); // 2\nhowManyTimes(100, 0); // 0\nhowManyTimes(100, -1); // Infinity",
+          "heronArea(3, 4, 5); // 6",
+          "const httpDelete = (url, callback, err = console.error) => {\n  const request = new XMLHttpRequest();\n  request.open('DELETE', url, true);\n  request.onload = () => callback(request);\n  request.onerror = () => err(request);\n  request.send();\n};",
+          "httpDelete('https://website.com/users/123', request => {\n  console.log(request.responseText);\n}); // 'Deletes a user from the database'",
           "const httpPut = (url, data, callback, err = console.error) => {\n  const request = new XMLHttpRequest();\n  request.open(\"PUT\", url, true);\n  request.setRequestHeader('Content-type','application/json; charset=utf-8');\n  request.onload = () => callback(request);\n  request.onerror = () => err(request);\n  request.send(data);\n};",
           "const password = \"fooBaz\";\nconst data = JSON.stringify(password);\nhttpPut('https://website.com/users/123', data, request => {\n  console.log(request.responseText);\n}); // 'Updates a user's password in database'",
           "const isArmstrongNumber = digits =>\n  (arr => arr.reduce((a, d) => a + parseInt(d) ** arr.length, 0) == digits)(\n    (digits + '').split('')\n  );",
@@ -315,14 +334,14 @@
           "removeVowels(\"foobAr\"); // \"fbr\"\nremoveVowels(\"foobAr\",\"*\"); // \"f**b*r\"",
           "const solveRPN = rpn => {\n  const OPERATORS = {\n    '*': (a, b) => a * b,\n    '+': (a, b) => a + b,\n    '-': (a, b) => a - b,\n    '/': (a, b) => a / b,\n    '**': (a, b) => a ** b\n  };\n  const [stack, solve] = [\n    [],\n    rpn\n      .replace(/\\^/g, '**')\n      .split(/\\s+/g)\n      .filter(el => !/\\s+/.test(el) && el !== '')\n  ];\n  solve.forEach(symbol => {\n    if (!isNaN(parseFloat(symbol)) && isFinite(symbol)) {\n      stack.push(symbol);\n    } else if (Object.keys(OPERATORS).includes(symbol)) {\n      const [a, b] = [stack.pop(), stack.pop()];\n      stack.push(OPERATORS[symbol](parseFloat(b), parseFloat(a)));\n    } else {\n      throw `${symbol} is not a recognized symbol`;\n    }\n  });\n  if (stack.length === 1) return stack.pop();\n  else throw `${rpn} is not a proper RPN. Please check it and try again`;\n};",
           "solveRPN('15 7 1 1 + - / 3 * 2 1 1 + + -'); // 5\nsolveRPN('2 3 ^'); // 8",
-          "const httpDelete = (url, callback, err = console.error) => {\n  const request = new XMLHttpRequest();\n  request.open('DELETE', url, true);\n  request.onload = () => callback(request);\n  request.onerror = () => err(request);\n  request.send();\n};",
+          "const howManyTimes = (num, divisor) => {\n  if (divisor === 1 || divisor === -1) return Infinity;\n  if (divisor === 0) return 0;\n  let i = 0;\n  while (Number.isInteger(num / divisor)) {\n    i++;\n    num = num / divisor;\n  }\n  return i;\n};",
-          "httpDelete('https://website.com/users/123', request => {\n  console.log(request.responseText);\n}); // 'Deletes a user from the database'"
+          "howManyTimes(100, 2); // 2\nhowManyTimes(100, 2.5); // 2\nhowManyTimes(100, 0); // 0\nhowManyTimes(100, -1); // Infinity"
         ],
         "tags": []
       },
       "meta": {
         "archived": true,
-        "hash": "923a1f48f03450680f6150058f7ae52edf8a08a0d00d57cf26aa803f707643c9"
+        "hash": "50abe1eb4fadd6d7d8ab5c5dc027f0bf34e6c391b6da1367ddee907abd741a30"
       }
     },
     {

snippets_archive/README.md

@@ -11,7 +11,8 @@ These snippets, while useful and interesting, didn't quite make it into the repo
 * [`factors`](#factors)
 * [`fibonacciCountUntilNum`](#fibonaccicountuntilnum)
 * [`fibonacciUntilNum`](#fibonacciuntilnum)
-* [`howManyTimes`](#howmanytimes)
+* [`heronArea`](#heronarea)
+* [`httpDelete`](#httpdelete)
 * [`httpPut`](#httpput)
 * [`isArmstrongNumber`](#isarmstrongnumber)
 * [`isSimilar`](#issimilar)
@@ -20,7 +21,7 @@ These snippets, while useful and interesting, didn't quite make it into the repo
 * [`quickSort`](#quicksort)
 * [`removeVowels`](#removevowels)
 * [`solveRPN`](#solverpn)
-* [`httpDelete`](#httpdelete)
+* [`howManyTimes`](#howmanytimes)
 
 ---
 ### JSONToDate
@@ -283,26 +284,19 @@ fibonacciUntilNum(10); // [ 0, 1, 1, 2, 3, 5, 8 ]
 
 <br>[⬆ Back to top](#table-of-contents)
 
-### howManyTimes
+### heronArea
 
-Returns the number of times `num` can be divided by `divisor` (integer or fractional) without getting a fractional answer.
+Returns the area of a triangle using only the 3 side lengths, Heron's formula. Assumes that the sides define a valid triangle. Does NOT assume it is a right triangle.
-Works for both negative and positive integers.
+
+More information on what Heron's formula is and why it works available here: https://en.wikipedia.org/wiki/Heron%27s_formula.
+
+Uses `Math.sqrt()` to find the square root of a value.
 
-If `divisor` is `-1` or `1` return `Infinity`.
-If `divisor` is `-0` or `0` return `0`.
-Otherwise, keep dividing `num` with `divisor` and incrementing `i`, while the result is an integer.
-Return the number of times the loop was executed, `i`.
 
 ```js
-const howManyTimes = (num, divisor) => {
+const heronArea = (side_a, side_b, side_c) => {
-  if (divisor === 1 || divisor === -1) return Infinity;
+    const p = (side_a + side_b + side_c) / 2
-  if (divisor === 0) return 0;
+    return Math.sqrt(p * (p-side_a) * (p-side_b) * (p-side_c))
-  let i = 0;
-  while (Number.isInteger(num / divisor)) {
-    i++;
-    num = num / divisor;
-  }
-  return i;
   };
 ```
 
@@ -310,10 +304,39 @@ const howManyTimes = (num, divisor) => {
 <summary>Examples</summary>
 
 ```js
-howManyTimes(100, 2); // 2
+heronArea(3, 4, 5); // 6
-howManyTimes(100, 2.5); // 2
+```
-howManyTimes(100, 0); // 0
+
-howManyTimes(100, -1); // Infinity
+</details>
+
+<br>[⬆ Back to top](#table-of-contents)
+
+### httpDelete
+
+Makes a `DELETE` request to the passed URL.
+
+Use `XMLHttpRequest` web api to make a `delete` request to the given `url`.
+Handle the `onload` event, by running the provided `callback` function.
+Handle the `onerror` event, by running the provided `err` function.
+Omit the third argument, `err` to log the request to the console's error stream by default.
+
+```js
+const httpDelete = (url, callback, err = console.error) => {
+  const request = new XMLHttpRequest();
+  request.open('DELETE', url, true);
+  request.onload = () => callback(request);
+  request.onerror = () => err(request);
+  request.send();
+};
+```
+
+<details>
+<summary>Examples</summary>
+
+```js
+httpDelete('https://website.com/users/123', request => {
+  console.log(request.responseText);
+}); // 'Deletes a user from the database'
 ```
 
 </details>
@@ -588,22 +611,26 @@ solveRPN('2 3 ^'); // 8
 
 <br>[⬆ Back to top](#table-of-contents)
 
-### httpDelete
+### howManyTimes
 
-Makes a `DELETE` request to the passed URL.
+Returns the number of times `num` can be divided by `divisor` (integer or fractional) without getting a fractional answer.
+Works for both negative and positive integers.
 
-Use `XMLHttpRequest` web api to make a `delete` request to the given `url`.
+If `divisor` is `-1` or `1` return `Infinity`.
-Handle the `onload` event, by running the provided `callback` function.
+If `divisor` is `-0` or `0` return `0`.
-Handle the `onerror` event, by running the provided `err` function.
+Otherwise, keep dividing `num` with `divisor` and incrementing `i`, while the result is an integer.
-Omit the third argument, `err` to log the request to the console's error stream by default.
+Return the number of times the loop was executed, `i`.
 
 ```js
-const httpDelete = (url, callback, err = console.error) => {
+const howManyTimes = (num, divisor) => {
-  const request = new XMLHttpRequest();
+  if (divisor === 1 || divisor === -1) return Infinity;
-  request.open('DELETE', url, true);
+  if (divisor === 0) return 0;
-  request.onload = () => callback(request);
+  let i = 0;
-  request.onerror = () => err(request);
+  while (Number.isInteger(num / divisor)) {
-  request.send();
+    i++;
+    num = num / divisor;
+  }
+  return i;
 };
 ```
 
@@ -611,9 +638,10 @@ const httpDelete = (url, callback, err = console.error) => {
 <summary>Examples</summary>
 
 ```js
-httpDelete('https://website.com/users/123', request => {
+howManyTimes(100, 2); // 2
-  console.log(request.responseText);
+howManyTimes(100, 2.5); // 2
-}); // 'Deletes a user from the database'
+howManyTimes(100, 0); // 0
+howManyTimes(100, -1); // Infinity
 ```
 
 </details>

static-parts/README-start.md

@@ -2,8 +2,9 @@
 
 # 30 seconds of code
 
-[![License](https://img.shields.io/badge/license-CC0--1.0-blue.svg)](https://github.com/30-seconds/30-seconds-of-code/blob/master/LICENSE) [![npm Downloads](https://img.shields.io/npm/dt/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![npm Version](https://img.shields.io/npm/v/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.com/30-seconds/30-seconds-of-code.svg?branch=master)](https://travis-ci.com/30-seconds/30-seconds-of-code) [![Codacy Badge](https://api.codacy.com/project/badge/Grade/6ab7791fb1ea40b4a576d658fb96807f)](https://www.codacy.com/app/Chalarangelo/30-seconds-of-code?utm_source=github.com&utm_medium=referral&utm_content=30-seconds/30-seconds-of-code&utm_campaign=Badge_Grade) [![Maintainability](https://api.codeclimate.com/v1/badges/4b8c1e099135f2d53413/maintainability)](https://codeclimate.com/github/30-seconds/30-seconds-of-code/maintainability) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) [![Known Vulnerabilities](https://snyk.io/test/github/30-seconds/30-seconds-of-code/badge.svg?targetFile=package.json)](https://snyk.io/test/github/30-seconds/30-seconds-of-code?targetFile=package.json) [![ProductHunt](https://img.shields.io/badge/producthunt-vote-orange.svg)](https://www.producthunt.com/posts/30-seconds-of-code)
+> *This README is built using [markdown-builder](https://github.com/30-seconds/markdown-builder).*
 
+[![License](https://img.shields.io/badge/license-CC0--1.0-blue.svg)](https://github.com/30-seconds/30-seconds-of-code/blob/master/LICENSE) [![npm Downloads](https://img.shields.io/npm/dt/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![npm Version](https://img.shields.io/npm/v/30-seconds-of-code.svg)](https://www.npmjs.com/package/30-seconds-of-code) [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-4FB999.svg)](https://gitter.im/30-seconds-of-code/Lobby) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com) [![Travis Build](https://travis-ci.com/30-seconds/30-seconds-of-code.svg?branch=master)](https://travis-ci.com/30-seconds/30-seconds-of-code) [![Codacy Badge](https://api.codacy.com/project/badge/Grade/6ab7791fb1ea40b4a576d658fb96807f)](https://www.codacy.com/app/Chalarangelo/30-seconds-of-code?utm_source=github.com&utm_medium=referral&utm_content=30-seconds/30-seconds-of-code&utm_campaign=Badge_Grade) [![Maintainability](https://api.codeclimate.com/v1/badges/4b8c1e099135f2d53413/maintainability)](https://codeclimate.com/github/30-seconds/30-seconds-of-code/maintainability) [![js-semistandard-style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) [![Known Vulnerabilities](https://snyk.io/test/github/30-seconds/30-seconds-of-code/badge.svg?targetFile=package.json)](https://snyk.io/test/github/30-seconds/30-seconds-of-code?targetFile=package.json) [![ProductHunt](https://img.shields.io/badge/producthunt-vote-orange.svg)](https://www.producthunt.com/posts/30-seconds-of-code)
 
 > Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 

test/getImages/getImages.js

@@ -1,5 +1,5 @@
 const getImages = (el, includeDuplicates = false) => {
-    const images = [...el.getElementsByTagName("img")].map(img => img.getAttribute("src"));
+  const images = [...el.getElementsByTagName('img')].map(img => img.getAttribute('src'));
-    return includeDuplicates ? images : [...(new Set(images))];
+  return includeDuplicates ? images : [...new Set(images)];
 };
 module.exports = getImages;

test/heronArea/heronArea.js

@@ -0,0 +1,5 @@
+const heronArea = (side_a, side_b, side_c) => {
+    const p = (side_a + side_b + side_c) / 2
+    return Math.sqrt(p * (p-side_a) * (p-side_b) * (p-side_c))
+  };
+module.exports = heronArea;

test/heronArea/heronArea.test.js

@@ -0,0 +1,6 @@
+const expect = require('expect');
+const heronArea = require('./heronArea.js');
+
+test('heronArea is a Function', () => {
+  expect(heronArea).toBeInstanceOf(Function);
+});