flatMap

Flattens nested iterable, based on map function. 🏃 [:vhs:] 📦 🌔

iterable.flatMap(x, [fn], [ths]);
// x:   a nested iterable
// fn:  map function (v, i, x)
// ths: this argument

const iterable = require('extra-iterable');

var x = [[1, 2], [3, [4, [5]]]];
[...iterable.flatMap(x)];
// [ 1, 2, 3, [ 4, [ 5 ] ] ]

[...iterable.flatMap(x, v => iterable.flat(v, 1))];
// [ 1, 2, 3, 4, [ 5 ] ]

[...iterable.flatMap(x, v => iterable.flat(v))];
// [ 1, 2, 3, 4, 5 ]

references

• Array.prototype.flatMap: MDN web docs
• _.flatten: lodash