replaceWith(orig, other)

Installation

npm i replace-with -S

Source (index.js)

/**
 * Replace an array|object's content with the other one's while keeping the reference
 * @param  {Array|Object} orig
 * @param  {Array|Object} other
 * @return {Array|Object} orig
 */
var keys = Object.keys;

module.exports = function replaceWith(orig, other) {
  if (Array.isArray(orig)) {
    // for Array
    orig.splice.apply(orig, [0, orig.length].concat(other));
  } else {
    // for Object
    keys(orig).forEach(function (k) { delete orig[k] });
    keys(other).forEach(function (k) { orig[k] = other[k] });
  }
  return orig;
};

Usage

Let's take a look at the test examples

test('replace array', t => {
  const orig = [1, 2, 3]
  const ref = orig
  replaceWith(orig, [4, 5, 6])
  t.is(ref, orig) // pass!
  t.deepEqual(orig, [4, 5, 6]) // pass!
})

test('replace object', t => {
  let orig = { a: 1, b: 2, c: 3 }
  const ref = orig
  orig = replaceWith(orig, { d: 4, e: 5, f: 6 })
  t.is(ref, orig) // pass!
  t.deepEqual(orig, { d: 4, e: 5, f: 6 }) // pass!
})

Test

npm test