How can I clone a JavaScript object except for one key?

If you use Babel you can use the following syntax to copy property b from x into variable b and then copy rest of properties into variable y:

let x = {a: 1, b: 2, c: 3, z:26};let {b, ...y} = x;

and it will be transpiled into:

"use strict";function _objectWithoutProperties(obj, keys) {  var target = {};  for (var i in obj) {    if (keys.indexOf(i) >= 0) continue;    if (!Object.prototype.hasOwnProperty.call(obj, i)) continue;    target[i] = obj[i];  }  return target;}var x = { a: 1, b: 2, c: 3, z: 26 };var b = x.b;var y = _objectWithoutProperties(x, ["b"]);

var clone = Object.assign({}, {a: 1, b: 2, c: 3});delete clone.b;

or if you accept property to be undefined:

var clone = Object.assign({}, {a: 1, b: 2, c: 3}, {b: undefined});

I use this ESNext one liner

const obj = { a: 1, b: 2, c: 3, d: 4 }const clone = (({ b, c, ...o }) => o)(obj) // remove b and cconsole.log(clone)