diff --git a/docs/adapter.html b/docs/adapter.html index 09c962a70..673c330be 100644 --- a/docs/adapter.html +++ b/docs/adapter.html @@ -79,7 +79,7 @@ document.getElementById('doc-drawer-checkbox').checked = false; } }, false); - }

logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.

 

Adapter

ary

Creates a function that accepts up to n arguments, ignoring any additional arguments.

Call the provided function, fn, with up to n arguments, using Array.slice(0,n) and the spread operator (...).

const ary = (fn, n) => (...args) => fn(...args.slice(0, n));
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Adapter
ary
Creates a function that accepts up to n arguments, ignoring any additional arguments.
Call the provided function, fn, with up to n arguments, using Array.slice(0,n) and the spread operator (...).
const ary = (fn, n) => (...args) => fn(...args.slice(0, n));
 
const firstTwoMax = ary(Math.max, 2);
 [[2, 6, 'a'], [8, 4, 6], [10]].map(x => firstTwoMax(...x)); // [6, 8, 10]
 
call
Given a key and a set of arguments, call them when given a context. Primarily useful in composition.
Use a closure to call a stored key with stored arguments.
const call = (key, ...args) => context => context[key](...args);
diff --git a/docs/archive.html b/docs/archive.html
index 551c8dfb3..8bceb9171 100644
--- a/docs/archive.html
+++ b/docs/archive.html
@@ -56,7 +56,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
Snippets Archive
These snippets, while useful and interesting, didn't quite make it into the repository due to either having very specific use-cases or being outdated. However we felt like they might still be useful to some readers, so here they are.

binarySearch
Use recursion. Similar to Array.indexOf() that finds the index of a value within an array. The difference being this operation only works with sorted arrays which offers a major performance boost due to it's logarithmic nature when compared to a linear search or Array.indexOf().
Search a sorted array by repeatedly dividing the search interval in half. Begin with an interval covering the whole array. If the value of the search is less than the item in the middle of the interval, recurse into the lower half. Otherwise recurse into the upper half. Repeatedly recurse until the value is found which is the mid or you've recursed to a point that is greater than the length which means the value doesn't exist and return -1.
const binarySearch = (arr, val, start = 0, end = arr.length - 1) => {
+      }
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
Snippets Archive
These snippets, while useful and interesting, didn't quite make it into the repository due to either having very specific use-cases or being outdated. However we felt like they might still be useful to some readers, so here they are.

binarySearch
Use recursion. Similar to Array.indexOf() that finds the index of a value within an array. The difference being this operation only works with sorted arrays which offers a major performance boost due to it's logarithmic nature when compared to a linear search or Array.indexOf().
Search a sorted array by repeatedly dividing the search interval in half. Begin with an interval covering the whole array. If the value of the search is less than the item in the middle of the interval, recurse into the lower half. Otherwise recurse into the upper half. Repeatedly recurse until the value is found which is the mid or you've recursed to a point that is greater than the length which means the value doesn't exist and return -1.
const binarySearch = (arr, val, start = 0, end = arr.length - 1) => {
   if (start > end) return -1;
   const mid = Math.floor((start + end) / 2);
   if (arr[mid] > val) return binarySearch(arr, val, start, mid - 1);
diff --git a/docs/array.html b/docs/array.html
index aae30e511..605f7fe74 100644
--- a/docs/array.html
+++ b/docs/array.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Array
all
Returns true if the provided predicate function returns true for all elements in a collection, false otherwise.
Use Array.every() to test if all elements in the collection return true based on fn. Omit the second argument, fn, to use Boolean as a default.
const all = (arr, fn = Boolean) => arr.every(fn);
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Array
all
Returns true if the provided predicate function returns true for all elements in a collection, false otherwise.
Use Array.every() to test if all elements in the collection return true based on fn. Omit the second argument, fn, to use Boolean as a default.
const all = (arr, fn = Boolean) => arr.every(fn);
 
all([4, 2, 3], x => x > 1); // true
 all([1, 2, 3]); // true
 
any
Returns true if the provided predicate function returns true for at least one element in a collection, false otherwise.
Use Array.some() to test if any elements in the collection return true based on fn. Omit the second argument, fn, to use Boolean as a default.
const any = (arr, fn = Boolean) => arr.some(fn);
diff --git a/docs/beginner.html b/docs/beginner.html
index b5f2e3a2e..2226ddbd7 100644
--- a/docs/beginner.html
+++ b/docs/beginner.html
@@ -56,7 +56,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
Snippets for Beginners
The following section is aimed towards individuals who are at the start of their web developer journey. Each snippet in the next section is simple yet very educational for newcomers. This section is by no means a complete resource for learning modern JavaScript. However, it is enough to grasp some common concepts and use cases. We also strongly recommend checking out MDN web docs as a learning resource.

currentURL
Returns the current URL.
Use window.location.href to get current URL.
const currentURL = () => window.location.href;
+      }
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
Snippets for Beginners
The following section is aimed towards individuals who are at the start of their web developer journey. Each snippet in the next section is simple yet very educational for newcomers. This section is by no means a complete resource for learning modern JavaScript. However, it is enough to grasp some common concepts and use cases. We also strongly recommend checking out MDN web docs as a learning resource.

currentURL
Returns the current URL.
Use window.location.href to get current URL.
const currentURL = () => window.location.href;
 
currentURL(); // 'https://google.com'
 
everyNth
Returns every nth element in an array.
Use Array.filter() to create a new array that contains every nth element of a given array.
const everyNth = (arr, nth) => arr.filter((e, i) => i % nth === nth - 1);
 
everyNth([1, 2, 3, 4, 5, 6], 2); // [ 2, 4, 6 ]
diff --git a/docs/browser.html b/docs/browser.html
index d1a5d28e4..ed2a8e5d3 100644
--- a/docs/browser.html
+++ b/docs/browser.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Browser
arrayToHtmlList
Converts the given array elements into <li> tags and appends them to the list of the given id.
Use Array.map() and document.querySelector() to create a list of html tags.
const arrayToHtmlList = (arr, listID) =>
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Browser
arrayToHtmlList
Converts the given array elements into <li> tags and appends them to the list of the given id.
Use Array.map() and document.querySelector() to create a list of html tags.
const arrayToHtmlList = (arr, listID) =>
   arr.map(item => (document.querySelector('#' + listID).innerHTML += `<li>${item}</li>`));
 
arrayToHtmlList(['item 1', 'item 2'], 'myListID');
 
bottomVisible
Returns true if the bottom of the page is visible, false otherwise.
Use scrollY, scrollHeight and clientHeight to determine if the bottom of the page is visible.
const bottomVisible = () =>
diff --git a/docs/date.html b/docs/date.html
index 0e8d720de..df810bbbd 100644
--- a/docs/date.html
+++ b/docs/date.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Date
formatDuration
Returns the human readable format of the given number of milliseconds.
Divide ms with the appropriate values to obtain the appropriate values for day, hour, minute, second and millisecond. Use Object.entries() with Array.filter() to keep only non-zero values. Use Array.map() to create the string for each value, pluralizing appropriately. Use String.join(', ') to combine the values into a string.
const formatDuration = ms => {
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Date
formatDuration
Returns the human readable format of the given number of milliseconds.
Divide ms with the appropriate values to obtain the appropriate values for day, hour, minute, second and millisecond. Use Object.entries() with Array.filter() to keep only non-zero values. Use Array.map() to create the string for each value, pluralizing appropriately. Use String.join(', ') to combine the values into a string.
const formatDuration = ms => {
   if (ms < 0) ms = -ms;
   const time = {
     day: Math.floor(ms / 86400000),
diff --git a/docs/function.html b/docs/function.html
index 3ea23494b..23df1ce1b 100644
--- a/docs/function.html
+++ b/docs/function.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Function
attempt
Attempts to invoke a function with the provided arguments, returning either the result or the caught error object.
Use a try... catch block to return either the result of the function or an appropriate error.
const attempt = (fn, ...args) => {
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Function
attempt
Attempts to invoke a function with the provided arguments, returning either the result or the caught error object.
Use a try... catch block to return either the result of the function or an appropriate error.
const attempt = (fn, ...args) => {
   try {
     return fn(...args);
   } catch (e) {
diff --git a/docs/index.html b/docs/index.html
index ac4322cf9..08199f210 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -1,4 +1,4 @@
-30 seconds of code
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
298
snippets
114
contributors
3117
commits
19573
stars
Our philosophy
The core goal of 30 seconds of code is to provide a quality resource for beginner and advanced JavaScript developers alike. We want to help improve the JavaScript ecosystem, by lowering the barrier of entry for newcomers and help seasoned veterans pick up new tricks and remember old ones. In order to achieve this, we have collected hundreds of snippets that can be of use in a wide range of situations. We welcome new contributors and we like fresh ideas, as long as the code is short and easy to grasp in about 30 seconds. The only catch, if you may, is that many of our snippets are not perfectly suited for large, enterprise applications and they might not be deemed production-ready.

In order for 30 seconds of code to be as accessible and useful as possible, all of the snippets in the collection are licensed under the CC0-1.0 License, meaning they are absolutely free to use in any project you like. If you like what we do, you can always credit us, but that is not mandatory.

Today's picks
Our sophisticated robot helpers pick new snippets from our collection daily, so that you can discover new snippets to enhance your projects:
 
hz
Returns the number of times a function executed per second. hz is the unit for hertz, the unit of frequency defined as one cycle per second.
Use performance.now() to get the difference in milliseconds before and after the iteration loop to calculate the time elapsed executing the function iterations times. Return the number of cycles per second by converting milliseconds to seconds and dividing it by the time elapsed. Omit the second argument, iterations, to use the default of 100 iterations.
const hz = (fn, iterations = 100) => {
+30 seconds of code
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
298
snippets
114
contributors
3117
commits
19573
stars
Our philosophy
The core goal of 30 seconds of code is to provide a quality resource for beginner and advanced JavaScript developers alike. We want to help improve the JavaScript ecosystem, by lowering the barrier of entry for newcomers and help seasoned veterans pick up new tricks and remember old ones. In order to achieve this, we have collected hundreds of snippets that can be of use in a wide range of situations. We welcome new contributors and we like fresh ideas, as long as the code is short and easy to grasp in about 30 seconds. The only catch, if you may, is that many of our snippets are not perfectly suited for large, enterprise applications and they might not be deemed production-ready.

In order for 30 seconds of code to be as accessible and useful as possible, all of the snippets in the collection are licensed under the CC0-1.0 License, meaning they are absolutely free to use in any project you like. If you like what we do, you can always credit us, but that is not mandatory.

Today's picks
Our sophisticated robot helpers pick new snippets from our collection daily, so that you can discover new snippets to enhance your projects:
 
hz
Returns the number of times a function executed per second. hz is the unit for hertz, the unit of frequency defined as one cycle per second.
Use performance.now() to get the difference in milliseconds before and after the iteration loop to calculate the time elapsed executing the function iterations times. Return the number of cycles per second by converting milliseconds to seconds and dividing it by the time elapsed. Omit the second argument, iterations, to use the default of 100 iterations.
const hz = (fn, iterations = 100) => {
   const before = performance.now();
   for (let i = 0; i < iterations; i++) fn();
   return 1000 * iterations / (performance.now() - before);
diff --git a/docs/math.html b/docs/math.html
index bb82f4270..280403503 100644
--- a/docs/math.html
+++ b/docs/math.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Math
approximatelyEqual
Checks if two numbers are approximately equal to each other.
Use Math.abs() to compare the absolute difference of the two values to epsilon. Omit the third parameter, epsilon, to use a default value of 0.001.
const approximatelyEqual = (v1, v2, epsilon = 0.001) => Math.abs(v1 - v2) < epsilon;
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Math
approximatelyEqual
Checks if two numbers are approximately equal to each other.
Use Math.abs() to compare the absolute difference of the two values to epsilon. Omit the third parameter, epsilon, to use a default value of 0.001.
const approximatelyEqual = (v1, v2, epsilon = 0.001) => Math.abs(v1 - v2) < epsilon;
 
approximatelyEqual(Math.PI / 2.0, 1.5708); // true
 
average
Returns the average of two or more numbers.
Use Array.reduce() to add each value to an accumulator, initialized with a value of 0, divide by the length of the array.
const average = (...nums) => [...nums].reduce((acc, val) => acc + val, 0) / nums.length;
 
average(...[1, 2, 3]); // 2
diff --git a/docs/node.html b/docs/node.html
index fdff7ce18..aa15e8bc1 100644
--- a/docs/node.html
+++ b/docs/node.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Node
atob
Decodes a string of data which has been encoded using base-64 encoding.
Create a Buffer for the given string with base-64 encoding and use Buffer.toString('binary') to return the decoded string.
const atob = str => new Buffer(str, 'base64').toString('binary');
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Node
atob
Decodes a string of data which has been encoded using base-64 encoding.
Create a Buffer for the given string with base-64 encoding and use Buffer.toString('binary') to return the decoded string.
const atob = str => new Buffer(str, 'base64').toString('binary');
 
atob('Zm9vYmFy'); // 'foobar'
 
btoa
Creates a base-64 encoded ASCII string from a String object in which each character in the string is treated as a byte of binary data.
Create a Buffer for the given string with binary encoding and use Buffer.toString('base64') to return the encoded string.
const btoa = str => new Buffer(str, 'binary').toString('base64');
 
btoa('foobar'); // 'Zm9vYmFy'
diff --git a/docs/object.html b/docs/object.html
index e34b44350..9a5e2e81b 100644
--- a/docs/object.html
+++ b/docs/object.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Object
bindAll
Binds methods of an object to the object itself, overwriting the existing method.
Use Array.forEach() to return a function that uses Function.apply() to apply the given context (obj) to fn for each function specified.
const bindAll = (obj, ...fns) =>
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Object
bindAll
Binds methods of an object to the object itself, overwriting the existing method.
Use Array.forEach() to return a function that uses Function.apply() to apply the given context (obj) to fn for each function specified.
const bindAll = (obj, ...fns) =>
   fns.forEach(
     fn => (
       (f = obj[fn]),
diff --git a/docs/string.html b/docs/string.html
index db3972669..ac365e7d2 100644
--- a/docs/string.html
+++ b/docs/string.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
String
byteSize
Returns the length of a string in bytes.
Convert a given string to a Blob Object and find its size.
const byteSize = str => new Blob([str]).size;
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
String
byteSize
Returns the length of a string in bytes.
Convert a given string to a Blob Object and find its size.
const byteSize = str => new Blob([str]).size;
 
byteSize('😀'); // 4
 byteSize('Hello World'); // 11
 
capitalize
Capitalizes the first letter of a string.
Use array destructuring and String.toUpperCase() to capitalize first letter, ...rest to get array of characters after first letter and then Array.join('') to make it a string again. Omit the lowerRest parameter to keep the rest of the string intact, or set it to true to convert to lowercase.
const capitalize = ([first, ...rest], lowerRest = false) =>
diff --git a/docs/type.html b/docs/type.html
index 133aaac3f..e5c72cb27 100644
--- a/docs/type.html
+++ b/docs/type.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Type
getType
Returns the native type of a value.
Returns lowercased constructor name of value, "undefined" or "null" if value is undefined or null.
const getType = v =>
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Type
getType
Returns the native type of a value.
Returns lowercased constructor name of value, "undefined" or "null" if value is undefined or null.
const getType = v =>
   v === undefined ? 'undefined' : v === null ? 'null' : v.constructor.name.toLowerCase();
 
getType(new Set([1, 2, 3])); // 'set'
 
is
Checks if the provided value is of the specified type.
Ensure the value is not undefined or null using Array.includes(), and compare the constructor property on the value with type to check if the provided value is of the specified type.
const is = (type, val) => ![, null].includes(val) && val.constructor === type;
diff --git a/docs/utility.html b/docs/utility.html
index 2511c7454..666498ca7 100644
--- a/docs/utility.html
+++ b/docs/utility.html
@@ -79,7 +79,7 @@
             document.getElementById('doc-drawer-checkbox').checked = false;
           }
         }, false);
-      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Utility
castArray
Casts the provided value as an array if it's not one.
Use Array.isArray() to determine if val is an array and return it as-is or encapsulated in an array accordingly.
const castArray = val => (Array.isArray(val) ? val : [val]);
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Utility
castArray
Casts the provided value as an array if it's not one.
Use Array.isArray() to determine if val is an array and return it as-is or encapsulated in an array accordingly.
const castArray = val => (Array.isArray(val) ? val : [val]);
 
castArray('foo'); // ['foo']
 castArray([1]); // [1]
 
cloneRegExp
Clones a regular expression.
Use new RegExp(), RegExp.source and RegExp.flags to clone the given regular expression.
const cloneRegExp = regExp => new RegExp(regExp.source, regExp.flags);
diff --git a/static-parts/archived-page-start.html b/static-parts/archived-page-start.html
index aec9410ad..c249ed188 100644
--- a/static-parts/archived-page-start.html
+++ b/static-parts/archived-page-start.html
@@ -84,7 +84,7 @@
     
   
   
-      
+      
     

       
logo 30 seconds of code

       
Curated collection of useful JavaScript snippets
 that you can understand in 30 seconds or less.

diff --git a/static-parts/beginner-page-start.html b/static-parts/beginner-page-start.html
index 501504e97..4ab08e6a0 100644
--- a/static-parts/beginner-page-start.html
+++ b/static-parts/beginner-page-start.html
@@ -84,7 +84,7 @@
     
   
   
-      
+      
     

       
logo 30 seconds of code

       
Curated collection of useful JavaScript snippets
 that you can understand in 30 seconds or less.

diff --git a/static-parts/index.html b/static-parts/index.html
index d32f3ec9d..3276ae908 100644
--- a/static-parts/index.html
+++ b/static-parts/index.html
@@ -23,7 +23,7 @@
     
   
   
-    
+    
     

   
logo 30 seconds of code

   
Curated collection of useful JavaScript snippets
 that you can understand in 30 seconds or less.

diff --git a/static-parts/page-start.html b/static-parts/page-start.html
index 742740ba3..88a8c8d0c 100644
--- a/static-parts/page-start.html
+++ b/static-parts/page-start.html
@@ -107,7 +107,7 @@
     
   
   
-    
+    
     

       
logo 30 seconds of code
         Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.