30-seconds-of-code/snippets/pullAtValue.md

title, tags, firstSeen, lastUpdated

title	tags	firstSeen	lastUpdated
pullAtValue	array,advanced	2017-12-19T08:06:29+02:00	2020-10-22T20:24:04+03:00

Mutates the original array to filter out the values specified. Returns the removed elements.

• Use Array.prototype.filter() and Array.prototype.includes() to pull out the values that are not needed.
• Set Array.prototype.length to mutate the passed in an array by resetting its length to 0.
• Use Array.prototype.push() to re-populate it with only the pulled values.
• Use Array.prototype.push() to keep track of pulled values.

const pullAtValue = (arr, pullArr) => {
  let removed = [],
    pushToRemove = arr.forEach((v, i) =>
      pullArr.includes(v) ? removed.push(v) : v
    ),
    mutateTo = arr.filter((v, i) => !pullArr.includes(v));
  arr.length = 0;
  mutateTo.forEach(v => arr.push(v));
  return removed;
};

let myArray = ['a', 'b', 'c', 'd'];
let pulled = pullAtValue(myArray, ['b', 'd']);
// myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ]