diff --git a/docs/index.html b/docs/index.html index 06e9d404c..90e05ac55 100644 --- a/docs/index.html +++ b/docs/index.html @@ -1,28 +1,33 @@ -30 seconds of code

logo 30 seconds of code

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

304
snippets

117
contributors

3197
commits

19928
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:

omitBy

Creates an object composed of the properties the given function returns falsey for. The function is invoked with two arguments: (value, key).

Use Object.keys(obj) and Array.filter()to remove the keys for which fn returns a truthy value. Use Array.reduce() to convert the filtered keys back to an object with the corresponding key-value pairs.

const omitBy = (obj, fn) =>
-  Object.keys(obj)
-    .filter(k => !fn(obj[k], k))
-    .reduce((acc, key) => ((acc[key] = obj[key]), acc), {});
-
omitBy({ a: 1, b: '2', c: 3 }, x => typeof x === 'number'); // { b: '2' }
-

readFileLines

Returns an array of lines from the specified file.

Use readFileSync function in fs node package to create a Buffer from a file. convert buffer to string using toString(encoding) function. creating an array from contents of file by spliting file content line by line (each \n).

const fs = require('fs');
-const readFileLines = filename =>
-  fs
-    .readFileSync(filename)
-    .toString('UTF8')
-    .split('\n');
-
/*
-contents of test.txt :
-  line1
-  line2
-  line3
-  ___________________________
-*/
-let arr = readFileLines('test.txt');
-console.log(arr); // ['line1', 'line2', 'line3']
-

splitLines

Splits a multiline string into an array of lines.

Use String.split() and a regular expression to match line breaks and create an array.

const splitLines = str => str.split(/\r?\n/);
-
splitLines('This\nis a\nmultiline\nstring.\n'); // ['This', 'is a', 'multiline', 'string.' , '']
+30 seconds of code
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
304
snippets
117
contributors
3198
commits
19936
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:
 
differenceWith
Filters out all values from an array for which the comparator function does not return true.
Use Array.filter() and Array.findIndex() to find the appropriate values.
const differenceWith = (arr, val, comp) => arr.filter(a => val.findIndex(b => comp(a, b)) === -1);
+
differenceWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0], (a, b) => Math.round(a) === Math.round(b)); // [1, 1.2]
+
rearg
Creates a function that invokes the provided function with its arguments arranged according to the specified indexes.
Use Array.reduce() and Array.indexOf() to reorder arguments based on indexes in combination with the spread operator (...) to pass the transformed arguments to fn.
const rearg = (fn, indexes) => (...args) =>
+  fn(
+    ...args.reduce(
+      (acc, val, i) => ((acc[indexes.indexOf(i)] = val), acc),
+      Array.from({ length: indexes.length })
+    )
+  );
+
var rearged = rearg(
+  function(a, b, c) {
+    return [a, b, c];
+  },
+  [2, 0, 1]
+);
+rearged('b', 'c', 'a'); // ['a', 'b', 'c']
+
toOrdinalSuffix
Adds an ordinal suffix to a number.
Use the modulo operator (%) to find values of single and tens digits. Find which ordinal pattern digits match. If digit is found in teens pattern, use teens ordinal.
const toOrdinalSuffix = num => {
+  const int = parseInt(num),
+    digits = [int % 10, int % 100],
+    ordinals = ['st', 'nd', 'rd', 'th'],
+    oPattern = [1, 2, 3, 4],
+    tPattern = [11, 12, 13, 14, 15, 16, 17, 18, 19];
+  return oPattern.includes(digits[0]) && !tPattern.includes(digits[1])
+    ? int + ordinals[digits[0] - 1]
+    : int + ordinals[3];
+};
+
toOrdinalSuffix('123'); // "123rd"
 

Getting started

Related projects
The idea behind 30 seconds of code has inspired some people to create similar collections in other programming languages and environments. Here are the ones we like the most:

Top contributors
chalarangelo Angelos Chalaris
fejes713 Stefan Feješ
flxwu Felix Wu
atomiks atomiks
kingdavidmartins King David Martins
kriadmin Rohit Tanwar
iamsoorena Soorena Soleimani
skatcat31 Robert Mennell
How to contribute
Do you have a cool idea for a new snippet? Maybe some code you use often and is not part of our collection? Contributing to 30 seconds of code is as simple as 1,2,3,4!
1
Create
Start by creating a snippet, according to the snippet template. Make sure to follow these simple guidelines:
  • Your snippet title must be unique and the same as the name of the implemented function.
  • Use the snippet description to explain what your snippet does and how it works.
  • Try to keep the snippet's code short and to the point. Use modern techniques and features.
  • Remember to provide an example of how your snippet works.
  • Your snippet should solve a real-world problem, no matter how simple.
  • Never modify README.md or any of the HTML files.
2
Tag
Run npm run tagger from your terminal, then open the tag_database file and tag your snippet appropriately. Multitagging is also supported, just make sure the first tag you specify is on of the major tags and the one that is most relevant to the implemneted function.
3
Test
You can optionally test your snippet to make our job easier. Simply run npm run tester to generate the test files for your snippet. Find the related folder for you snippet under the test directory and write some tests. Remember to run npm run tester again to make sure your tests are passing.
4
Pull request
If you have done everything mentioned above, you should now have an awesome snippet to add to our collection. Simply start a pull request and follow the guidelines provided. Remember to only submit one snippet per pull request, so that we can quickly evaluate and merge your code into the collection.
If you need additional pointers about writing a snippet, be sure to read the complete contribution guidelines.