filter$

Keep entries which pass a test.

Alternatives: filter, filter$.
Similar: filter, filterAt.
Similar: map, reduce, filter, reject.

function filter$(x, ft)
// x:  an object (updated)
// ft: test function (v, k, x)

const object = require('extra-object');

var x = {a: 1, b: 2, c: 3, d: 4, e: 5};
object.filter$(x, v => v % 2 === 1);
// → { a: 1, c: 3, e: 5 }

x;
// → { a: 1, c: 3, e: 5 }

var x = {a: 1, b: 2, c: 3, d: 4, e: 5};
object.filter$(x, v => v % 2 === 0);
// → { b: 2, d: 4 }