traverson/lib/merge_recursive.js

Hypermedia API/HATEOAS client for Node.js and the browser

'use strict';

// TODO Maybe replace with https://github.com/Raynos/xtend
// check browser build size, though.
function mergeRecursive(obj1, obj2) {
  if (!obj1 && obj2) {
    obj1 = {};
  }
  for (var key in obj2) {
    if (!obj2.hasOwnProperty(key)) {
      continue;
    }
    merge(obj1, obj2, key);
  }
  return obj1;
}

function merge(obj1, obj2, key) {
  if (typeof obj2[key] === 'object') {
    // if it is an object (that is, a non-leave in the tree),
    // and it is not present in obj1
    if (!obj1[key] || typeof obj1[key] !== 'object') {
      // ... we create an empty object in obj1
      obj1[key] = {};
    }
    // and we recurse deeper into the structure
    mergeRecursive(obj1[key], obj2[key]);
  } else {
    // if it is primitive (string, number, boolean) or a function, we overwrite/
    // add it to obj1
    obj1[key] = obj2[key];
  }
}

module.exports = mergeRecursive;