Array methods ponyfills UX utilities

index.js

// Assume we have ponyfilled versions of array methods
const map = (arr, cb) => [].map.call(arr, cb);
const reduce = (arr, cb) => [].reduce.call(arr, cb);

// What we wanna do without ponyfills
const res = [1,2,3]
  .map(x => x * 10)
  .reduce((cur, prev) => cur + prev);

// What we can do with ponyfills
const foo = map([1,2,3], x => x * 10);
const res1 = reduce(foo, (cur, prev) => cur + prev);

/**
  * Pipe utility function
  * Allows for piping array functions in more declarative way
  */

const pipe = funcs => initialValue => {
  let value = initialValue;
  funcs.forEach(([fn, ...additionalArgs]) => {
      value = fn(value, ...additionalArgs);
  });
  return value;
}

const res2 = pipe([
  [map, x => x * 10],
  [reduce, (cur, prev) => cur + prev]
])([1,2,3]);

console.assert(res1 === res2)

/**
  * IterableArray wrapper
  * Allows for chaining almost like with causal array functions
  */

class IterableArray {
  constructor(arr) {
    this.val = arr;
  }
  
  map(cb) {
    this.val = map(this.val, cb);
    return this;
  }
  
  reduce(cb) {
    this.val = reduce(this.val, cb);
    return this;
  }
  
  toValue() {
    return this.val;
  }
}

const iter = (arr) => new IterableArray(arr);


const res3 = iter([1,2,3])
  .map(x => x * 10)
  .reduce((cur, prev) => cur + prev)
  .toValue();

console.assert(res1 === res3)