JavaScript – Higher Order functions & filter

Lately I have been watching a really good series on the fundamentals of JavaScript from mpj. Here are my notes.

Because JS is a function based languages, functions play a much larger role in JS then they do in other languages. They are treated like variables and passed around.

In this case Array.prototype.filter() returns a new array based on whether the predicate returns true or false for each element of the array.

var words = ["spray", "limit", "elite", "exuberant", "destruction", "present"];

var longWords = words.filter(function(word){
  return word.length > 6;
});

E6 version

const words = ["spray", "limit", "elite", "exuberant", "destruction", "present"];

let longWords = words.filter(word => word.length > 6);

Video.

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