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JavaScript: Mutate the original array to filter out the values specified

JavaScript fundamental (ES6 Syntax): Exercise-161 with Solution

Write a JavaScript program to mutate 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.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
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']); 
console.log('Original data',myArray);
console.log('Pulled data',pulled);

Sample Output:

"Original data"
["a", "c"]
"Pulled data"
["b", "d"]

Flowchart:

flowchart: Mutate the original array to filter out the values specified

Live Demo:

See the Pen javascript-basic-exercise-161-1 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found: 

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv