From 3d09f3bc18db0699df6130bfda79bbe85e738702 Mon Sep 17 00:00:00 2001 From: 30secondsofcode <30secondsofcode@gmail.com> Date: Wed, 1 Aug 2018 19:50:04 +0000 Subject: [PATCH] Travis build: 156 [cron] --- docs/index.html | 63 +- test/testlog | 3050 +++++++++++++++++++++++------------------------ 2 files changed, 1576 insertions(+), 1537 deletions(-) diff --git a/docs/index.html b/docs/index.html index 0a19bacd9..e2a588e45 100644 --- a/docs/index.html +++ b/docs/index.html @@ -1,17 +1,56 @@ -30 seconds of code

logo 30 seconds of code

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

318
snippets

121
contributors

3455
commits

21209
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:

findLastIndex

Returns the index of the last element for which the provided function returns a truthy value.

Use Array.map() to map each element to an array with its index and value. Use Array.filter() to remove elements for which fn returns falsey values, Array.pop() to get the last one.

const findLastIndex = (arr, fn) =>
-  arr
-    .map((val, i) => [i, val])
-    .filter(([i, val]) => fn(val, i, arr))
-    .pop()[0];
-
findLastIndex([1, 2, 3, 4], n => n % 2 === 1); // 2 (index of the value 3)
-

getStyle

Returns the value of a CSS rule for the specified element.

Use Window.getComputedStyle() to get the value of the CSS rule for the specified element.

const getStyle = (el, ruleName) => getComputedStyle(el)[ruleName];
-
getStyle(document.querySelector('p'), 'font-size'); // '16px'
-

redirect

Redirects to a specified URL.

Use window.location.href or window.location.replace() to redirect to url. Pass a second argument to simulate a link click (true - default) or an HTTP redirect (false).

const redirect = (url, asLink = true) =>
-  asLink ? (window.location.href = url) : window.location.replace(url);
-
redirect('https://google.com');
+30 seconds of code
logo 30 seconds of code
Curated collection of useful JavaScript snippets
that you can understand in 30 seconds or less.
318
snippets
121
contributors
3456
commits
21222
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:
 
flattenObject
Flatten an object with the paths for keys.
Use recursion. Use Object.keys(obj) combined with Array.reduce() to convert every leaf node to a flattened path node. If the value of a key is an object, the function calls itself with the appropriate prefix to create the path using Object.assign(). Otherwise, it adds the appropriate prefixed key-value pair to the accumulator object. You should always omit the second argument, prefix, unless you want every key to have a prefix.
const flattenObject = (obj, prefix = '') =>
+  Object.keys(obj).reduce((acc, k) => {
+    const pre = prefix.length ? prefix + '.' : '';
+    if (typeof obj[k] === 'object') Object.assign(acc, flattenObject(obj[k], pre + k));
+    else acc[pre + k] = obj[k];
+    return acc;
+  }, {});
+
flattenObject({ a: { b: { c: 1 } }, d: 1 }); // { 'a.b.c': 1, d: 1 }
+
getURLParameters
Returns an object containing the parameters of the current URL.
Use String.match() with an appropriate regular expression to get all key-value pairs, Array.reduce() to map and combine them into a single object. Pass location.search as the argument to apply to the current url.
const getURLParameters = url =>
+  (url.match(/([^?=&]+)(=([^&]*))/g) || []).reduce(
+    (a, v) => ((a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a),
+    {}
+  );
+
getURLParameters('http://url.com/page?name=Adam&surname=Smith'); // {name: 'Adam', surname: 'Smith'}
+getURLParameters('google.com'); // {}
+
runAsync
Runs a function in a separate thread by using a Web Worker, allowing long running functions to not block the UI.
Create a new Worker using a Blob object URL, the contents of which should be the stringified version of the supplied function. Immediately post the return value of calling the function back. Return a promise, listening for onmessage and onerror events and resolving the data posted back from the worker, or throwing an error.
const runAsync = fn => {
+  const worker = new Worker(
+    URL.createObjectURL(new Blob([`postMessage((${fn})());`]), {
+      type: 'application/javascript; charset=utf-8'
+    })
+  );
+  return new Promise((res, rej) => {
+    worker.onmessage = ({ data }) => {
+      res(data), worker.terminate();
+    };
+    worker.onerror = err => {
+      rej(err), worker.terminate();
+    };
+  });
+};
+
const longRunningFunction = () => {
+  let result = 0;
+  for (let i = 0; i < 1000; i++) {
+    for (let j = 0; j < 700; j++) {
+      for (let k = 0; k < 300; k++) {
+        result = result + i + j + k;
+      }
+    }
+  }
+  return result;
+};
+/*
+  NOTE: Since the function is running in a different context, closures are not supported.
+  The function supplied to `runAsync` gets stringified, so everything becomes literal.
+  All variables and functions must be defined inside.
+*/
+runAsync(longRunningFunction).then(console.log); // 209685000000
+runAsync(() => 10 ** 3).then(console.log); // 1000
+let outsideVariable = 50;
+runAsync(() => typeof outsideVariable).then(console.log); // 'undefined'
 

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.