From 8e60551a23b3d61b652efec26de411d9c982e51d Mon Sep 17 00:00:00 2001 From: 30secondsofcode <30secondsofcode@gmail.com> Date: Sat, 1 Sep 2018 20:05:19 +0000 Subject: [PATCH] Travis build: 342 [cron] --- docs/index.html | 45 +- snippet_data/snippets.json | 20 + test/deepFreeze/deepFreeze.js | 21 +- test/testlog | 3238 +++++++++++++++++---------------- 4 files changed, 1664 insertions(+), 1660 deletions(-) diff --git a/docs/index.html b/docs/index.html index 5e2b183ad..b02ef0164 100644 --- a/docs/index.html +++ b/docs/index.html @@ -1,33 +1,24 @@ -30 seconds of code

logo 30 seconds of code

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

320
snippets

125
contributors

3595
commits

21541
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 a few of our snippets are not perfectly optimized 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:

debounce

Creates a debounced function that delays invoking the provided function until at least ms milliseconds have elapsed since the last time it was invoked.

Each time the debounced function is invoked, clear the current pending timeout with clearTimeout() and use setTimeout() to create a new timeout that delays invoking the function until at least ms milliseconds has elapsed. Use Function.apply() to apply the this context to the function and provide the necessary arguments. Omit the second argument, ms, to set the timeout at a default of 0 ms.

const debounce = (fn, ms = 0) => {
-  let timeoutId;
-  return function(...args) {
-    clearTimeout(timeoutId);
-    timeoutId = setTimeout(() => fn.apply(this, args), ms);
-  };
+30 seconds of code
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
321
snippets
125
contributors
3601
commits
21552
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 a few of our snippets are not perfectly optimized 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:
 
initializeNDArray
Create a n-dimensional array with given value.
Use recursion. Use Array.map() to generate rows where each is a new array initialized using initializeNDArray.
const initializeNDArray = (val, ...args) =>
+  args.length === 0
+    ? val
+    : Array.from({ length: args[0] }).map(() => initializeNDArray(val, ...args.slice(1)));
+
initializeNDArray(1, 3); // [1,1,1]
+initializeNDArray(5, 2, 2, 2); // [[[5,5],[5,5]],[[5,5],[5,5]]]
+
isNull
Returns true if the specified value is null, false otherwise.
Use the strict equality operator to check if the value and of val are equal to null.
const isNull = val => val === null;
+
isNull(null); // true
+
sampleSize
Gets n random elements at unique keys from array up to the size of array.
Shuffle the array using the Fisher-Yates algorithm. Use Array.slice() to get the first n elements. Omit the second argument, n to get only one element at random from the array.
const sampleSize = ([...arr], n = 1) => {
+  let m = arr.length;
+  while (m) {
+    const i = Math.floor(Math.random() * m--);
+    [arr[m], arr[i]] = [arr[i], arr[m]];
+  }
+  return arr.slice(0, n);
 };
-
window.addEventListener(
-  'resize',
-  debounce(() => {
-    console.log(window.innerWidth);
-    console.log(window.innerHeight);
-  }, 250)
-); // Will log the window dimensions at most every 250ms
-
flip
Flip takes a function as an argument, then makes the first argument the last.
Return a closure that takes variadic inputs, and splices the last argument to make it the first argument before applying the rest.
const flip = fn => (first, ...rest) => fn(...rest, first);
-
let a = { name: 'John Smith' };
-let b = {};
-const mergeFrom = flip(Object.assign);
-let mergePerson = mergeFrom.bind(null, a);
-mergePerson(b); // == b
-b = {};
-Object.assign(b, a); // == b
-
omit
Omits the key-value pairs corresponding to the given keys from an object.
Use Object.keys(obj), Array.filter() and Array.includes() to remove the provided keys. Use Array.reduce() to convert the filtered keys back to an object with the corresponding key-value pairs.
const omit = (obj, arr) =>
-  Object.keys(obj)
-    .filter(k => !arr.includes(k))
-    .reduce((acc, key) => ((acc[key] = obj[key]), acc), {});
-
omit({ a: 1, b: '2', c: 3 }, ['b']); // { 'a': 1, 'c': 3 }
+
sampleSize([1, 2, 3], 2); // [3,1]
+sampleSize([1, 2, 3], 4); // [2,3,1]
 

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 implemented 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.