dot-component/index.js

MongoDB-style "dot notation" querying for JavaScript.

/**
 * Module dependencies.
 */

var type = require('type-component');

/**
 * Gets a certain `path` from the `obj`.
 *
 * @param {Object} target
 * @param {String} key
 * @return {Object} found object, or `undefined
 * @api public
 */

exports.get = function(obj, path){
  if (~path.indexOf('.')) {
    var par = parent(obj, path);
    var mainKey = path.split('.').pop();
    var t = type(par);
    if ('object' == t || 'array' == t) return par[mainKey];
  } else {
    return obj[path];
  }
};

/**
 * Sets the given `path` to `val` in `obj`.
 *
 * @param {Object} target
 * @Param {String} key
 * @param {Object} value
 * @api public
 */

exports.set = function(obj, path, val){
  if (~path.indexOf('.')) {
    var par = parent(obj, path, true);
    var mainKey = path.split('.').pop();
    if (par && 'object' == type(par)) par[mainKey] = val;
  } else {
    obj[path] = val;
  }
};

/**
 * Gets the parent object for a given key (dot notation aware).
 *
 * - If a parent object doesn't exist, it's initialized.
 * - Array index lookup is supported
 *
 * @param {Object} target object
 * @param {String} key
 * @param {Boolean} true if it should initialize the path
 * @api public
 */

exports.parent = parent;

function parent(obj, key, init){
  if (~key.indexOf('.')) {
    var pieces = key.split('.');
    var ret = obj;

    for (var i = 0; i < pieces.length - 1; i++) {
      // if the key is a number string and parent is an array
      if (Number(pieces[i]) == pieces[i] && 'array' == type(ret)) {
        ret = ret[pieces[i]];
      } else if ('object' == type(ret)) {
        if (init && !ret.hasOwnProperty(pieces[i])) {
          ret[pieces[i]] = {};
        }
        if (ret) ret = ret[pieces[i]];
      }
    }

    return ret;
  } else {
    return obj;
  }
}