Skip to main content

pullBy

JS TODO

Mutates the original array to filter out the values specified, based on a given iterator function.

Check if the last argument provided in a function. Use Array.prototype.map() to apply the iterator function fn to all array elements. Use Array.prototype.filter() and Array.prototype.includes() to pull out the values that are not needed. Use Array.prototype.length = 0 to mutate the passed in an array by resetting it's length to zero and Array.prototype.push() to re-populate it with only the pulled values.

const pullBy = (arr, ...args) => {
const length = args.length;
let fn = length > 1 ? args[length - 1] : undefined;
fn = typeof fn == "function" ? (args.pop(), fn) : undefined;
let argState = (Array.isArray(args[0]) ? args[0] : args).map((val) =>
fn(val)
);
let pulled = arr.filter((v, i) => !argState.includes(fn(v)));
arr.length = 0;
pulled.forEach((v) => arr.push(v));
};
var myArray = [{ x: 1 }, { x: 2 }, { x: 3 }, { x: 1 }];
pullBy(myArray, [{ x: 1 }, { x: 3 }], (o) => o.x); // myArray = [{ x: 2 }]