Objects.filter()

added in 0.5.0 • last revisions

Syntax

function filter<T extends object>(object: T, predicate: (value: T[typeof key], key: keyof T) => boolean): Partial<T>

Creates a new object from an existing one with only the keys and values that match a condition.

Parameters
`object`	The object to filter.
`predicate`	A predicate function that is called once for each enumerable key in the object and receives the value behind the key and the key itself as arguments. If this function returns `true`, the key and value are transferred to the new object.

Example

import { Objects } from 'potence';

const colors = {
    red: 0xff0000,
    yellow: 0xffff00,
    green: 0x00ff00,
    blue: 0x0000ff,
    purple: 0xff00ff,
    cyan: 0x00ffff
};

// bitwise and
Objects.filter(colors, color => (color & colors.blue) === colors.blue);
// returns:
// {
//     blue: 0x0000ff,
//     purple: 0xff00ff,
//     cyan: 0x00ffff
// }

Remarks

This function is analogous to Array.prototype.filter().

Note that this function does not perform any kind of copy on the key values. If the key values are references, you may wish to use Objects.map() to clone them after the filter operation.