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/**
* Copyright (c) 2013-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
*
* @typechecks
*/
'use strict';
/**
* Get a value from an object based on the given path
*
* Usage example:
*
* var obj = {
* a : {
* b : 123
* }
* };
*
* var result = getByPath(obj, ['a', 'b']); // 123
*
* You may also specify the path using an object with a path field
*
* var result = getByPath(obj, {path: ['a', 'b']}); // 123
*
* If the path doesn't exist undefined will be returned
*
* var result = getByPath(obj, ['x', 'y', 'z']); // undefined
*/
function getByPath(root
/*?Object | Error*/
, path, fallbackValue) {
var current = root;
for (var i = 0; i < path.length; i++) {
var segment = path[i]; // Use 'in' to check entire prototype chain since immutable js records
// use prototypes
if (current && segment in current) {
current = current[segment];
} else {
return fallbackValue;
}
}
return current;
}
module.exports = getByPath;