array-mat

Array concat => map rolled in a mat.

Install

npm install array-mat

Synopsis

mat takes an array A₀, a transform function F(A₀) => A₁ and returns a new array A₀ + A₁:

A.mat(F) /* ==> */ A.concat(A.map(F))

Given an array A₀ and N number of transforms A₀ + F(A₀) + ... + Fₙ(Fₙ₋₁(A))

A
  .mat(F[0])
  ...
  .mat(F[F.length - 1])

  // ==>

  A.concat(A.map(F[0]), ..., /* Aₙ₋₁ */.map(F[F.length - 1]))

Examples

["A", "B", "C"].mat((k)=>k.toLowerCase())
/* [ 'A', 'B', 'C', 'a', 'b', 'c' ] */

[].concat.apply([], ["A", "B"]
    .mat((file) => file.toLowerCase())
    .mat((file) => [file + ".js", file + ".es"]))
/*
  [
    'A','B','a','b',
    'A.js','A.es','B.js','B.es',
    'a.js','a.es','b.js','b.es'
  ]
*/

Extending the Prototype

Quoting @raynos:

Extending natives is a decision a library user should make, not a decision a library author should make.

You can extend the Array prototype like so:

Array.prototype.mat = Array.prototype.mat || require("array-mat")

console.log(
  [0]
    .mat((k) => k + 1 )
    .mat((k) => k + 2 )
    .mat((k) => k + 4 )
)

Or use as a standalone function. The return value of the first call to mat, will be an array with a non-enmurable mat method that you can use to create a chain of concat-transforms.

let mat = require("array-mat")

console.log(
  mat([0], (k) => k + 1)
    .mat((k) => k + 2)
    .mat((k) => k + 4)
)

Use node's --harmony flag for arrow function support.

» node --harmony example.js
[ 0, 1, 2, 3, 4, 5, 6, 7 ]

It's up to you. You can learn more about extending JavaScript natives here.

License

MIT © Jorge Bucaran