Array Higher Order Functions in JavaScript

Hello Daniel,

The [JavaScript Array prototype](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype) provides a number of what are fancily known as [higher-order functions](https://medium.com/humans-create-software/a-dirt-simple-introduction-to-higher-order-functions-in-javascript-b33bf9e19056). Apart from the usual suspects [Array.prototype.map()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map), [Array.prototype.filter()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter) and [Array.prototype.reduce()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce), there are the lesser known [Array.prototype.sort()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort), [Array.prototype.some()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some) and [Array.prototype.every()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every) higher-order functions, not to mention [Array.prototype.forEach()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach) is also one. Having learnt these recently in JavaScript as well as Swift, I find them a very powerful tool to add in the toolbox of a programmer of any skill. They make array operations look significantly more structured in code. However, I do not know how efficient they are, when it comes to how fast one’s code runs.

I am raising this issue to request you to make a video tutorial on these higher-order functions, to reiterate, as knowing and using them are a powerful skill and they make your source code look far more structured and undeniably intuitive.

Sincerely,
Prathamesh Kowarkar

Array.prototype.map()、filter()、reduce()、sort()、some()、every()、forEach() に関するリンク先の MDN リファレンスから始めてください。完了したコントリビューションでは、これらの高階関数、その体系的な使用方法、および issue のランタイム効率に関する質問を扱うビデオチュートリアルを作成します。

索引モデルが issue の本文から書いたものです。