// Copyright 2006 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @fileoverview Utilities for manipulating objects/maps/hashes.
* @author arv@google.com (Erik Arvidsson)
*/
goog.provide('goog.object');
/**
* Whether two values are not observably distinguishable. This
* correctly detects that 0 is not the same as -0 and two NaNs are
* practically equivalent.
*
* The implementation is as suggested by harmony:egal proposal.
*
* @param {*} v The first value to compare.
* @param {*} v2 The second value to compare.
* @return {boolean} Whether two values are not observably distinguishable.
* @see http://wiki.ecmascript.org/doku.php?id=harmony:egal
*/
goog.object.is = function(v, v2) {
if (v === v2) {
// 0 === -0, but they are not identical.
// We need the cast because the compiler requires that v2 is a
// number (although 1/v2 works with non-number). We cast to ? to
// stop the compiler from type-checking this statement.
return v !== 0 || 1 / v === 1 / /** @type {?} */ (v2);
}
// NaN is non-reflexive: NaN !== NaN, although they are identical.
return v !== v && v2 !== v2;
};
/**
* Calls a function for each element in an object/map/hash.
*
* @param {Object<K,V>} obj The object over which to iterate.
* @param {function(this:T,V,?,Object<K,V>):?} f The function to call
* for every element. This function takes 3 arguments (the value, the
* key and the object) and the return value is ignored.
* @param {T=} opt_obj This is used as the 'this' object within f.
* @template T,K,V
*/
goog.object.forEach = function(obj, f, opt_obj) {
for (var key in obj) {
f.call(/** @type {?} */ (opt_obj), obj[key], key, obj);
}
};
/**
* Calls a function for each element in an object/map/hash. If that call returns
* true, adds the element to a new object.
*
* @param {Object<K,V>} obj The object over which to iterate.
* @param {function(this:T,V,?,Object<K,V>):boolean} f The function to call
* for every element. This
* function takes 3 arguments (the value, the key and the object)
* and should return a boolean. If the return value is true the
* element is added to the result object. If it is false the
* element is not included.
* @param {T=} opt_obj This is used as the 'this' object within f.
* @return {!Object<K,V>} a new object in which only elements that passed the
* test are present.
* @template T,K,V
*/
goog.object.filter = function(obj, f, opt_obj) {
var res = {};
for (var key in obj) {
if (f.call(/** @type {?} */ (opt_obj), obj[key], key, obj)) {
res[key] = obj[key];
}
}
return res;
};
/**
* For every element in an object/map/hash calls a function and inserts the
* result into a new object.
*
* @param {Object<K,V>} obj The object over which to iterate.
* @param {function(this:T,V,?,Object<K,V>):R} f The function to call
* for every element. This function
* takes 3 arguments (the value, the key and the object)
* and should return something. The result will be inserted
* into a new object.
* @param {T=} opt_obj This is used as the 'this' object within f.
* @return {!Object<K,R>} a new object with the results from f.
* @template T,K,V,R
*/
goog.object.map = function(obj, f, opt_obj) {
var res = {};
for (var key in obj) {
res[key] = f.call(/** @type {?} */ (opt_obj), obj[key], key, obj);
}
return res;
};
/**
* Calls a function for each element in an object/map/hash. If any
* call returns true, returns true (without checking the rest). If
* all calls return false, returns false.
*
* @param {Object<K,V>} obj The object to check.
* @param {function(this:T,V,?,Object<K,V>):boolean} f The function to
* call for every element. This function
* takes 3 arguments (the value, the key and the object) and should
* return a boolean.
* @param {T=} opt_obj This is used as the 'this' object within f.
* @return {boolean} true if any element passes the test.
* @template T,K,V
*/
goog.object.some = function(obj, f, opt_obj) {
for (var key in obj) {
if (f.call(/** @type {?} */ (opt_obj), obj[key], key, obj)) {
return true;
}
}
return false;
};
/**
* Calls a function for each element in an object/map/hash. If
* all calls return true, returns true. If any call returns false, returns
* false at this point and does not continue to check the remaining elements.
*
* @param {Object<K,V>} obj The object to check.
* @param {?function(this:T,V,?,Object<K,V>):boolean} f The function to
* call for every element. This function
* takes 3 arguments (the value, the key and the object) and should
* return a boolean.
* @param {T=} opt_obj This is used as the 'this' object within f.
* @return {boolean} false if any element fails the test.
* @template T,K,V
*/
goog.object.every = function(obj, f, opt_obj) {
for (var key in obj) {
if (!f.call(/** @type {?} */ (opt_obj), obj[key], key, obj)) {
return false;
}
}
return true;
};
/**
* Returns the number of key-value pairs in the object map.
*
* @param {Object} obj The object for which to get the number of key-value
* pairs.
* @return {number} The number of key-value pairs in the object map.
*/
goog.object.getCount = function(obj) {
var rv = 0;
for (var key in obj) {
rv++;
}
return rv;
};
/**
* Returns one key from the object map, if any exists.
* For map literals the returned key will be the first one in most of the
* browsers (a know exception is Konqueror).
*
* @param {Object} obj The object to pick a key from.
* @return {string|undefined} The key or undefined if the object is empty.
*/
goog.object.getAnyKey = function(obj) {
for (var key in obj) {
return key;
}
};
/**
* Returns one value from the object map, if any exists.
* For map literals the returned value will be the first one in most of the
* browsers (a know exception is Konqueror).
*
* @param {Object<K,V>} obj The object to pick a value from.
* @return {V|undefined} The value or undefined if the object is empty.
* @template K,V
*/
goog.object.getAnyValue = function(obj) {
for (var key in obj) {
return obj[key];
}
};
/**
* Whether the object/hash/map contains the given object as a value.
* An alias for goog.object.containsValue(obj, val).
*
* @param {Object<K,V>} obj The object in which to look for val.
* @param {V} val The object for which to check.
* @return {boolean} true if val is present.
* @template K,V
*/
goog.object.contains = function(obj, val) {
return goog.object.containsValue(obj, val);
};
/**
* Returns the values of the object/map/hash.
*
* @param {Object<K,V>} obj The object from which to get the values.
* @return {!Array<V>} The values in the object/map/hash.
* @template K,V
*/
goog.object.getValues = function(obj) {
var res = [];
var i = 0;
for (var key in obj) {
res[i++] = obj[key];
}
return res;
};
/**
* Returns the keys of the object/map/hash.
*
* @param {Object} obj The object from which to get the keys.
* @return {!Array<string>} Array of property keys.
*/
goog.object.getKeys = function(obj) {
var res = [];
var i = 0;
for (var key in obj) {
res[i++] = key;
}
return res;
};
/**
* Get a value from an object multiple levels deep. This is useful for
* pulling values from deeply nested objects, such as JSON responses.
* Example usage: getValueByKeys(jsonObj, 'foo', 'entries', 3)
*
* @param {!Object} obj An object to get the value from. Can be array-like.
* @param {...(string|number|!IArrayLike<number|string>)}
* var_args A number of keys
* (as strings, or numbers, for array-like objects). Can also be
* specified as a single array of keys.
* @return {*} The resulting value. If, at any point, the value for a key
* is undefined, returns undefined.
*/
goog.object.getValueByKeys = function(obj, var_args) {
var isArrayLike = goog.isArrayLike(var_args);
var keys = isArrayLike ? var_args : arguments;
// Start with the 2nd parameter for the variable parameters syntax.
for (var i = isArrayLike ? 0 : 1; i < keys.length; i++) {
obj = obj[keys[i]];
if (!goog.isDef(obj)) {
break;
}
}
return obj;
};
/**
* Whether the object/map/hash contains the given key.
*
* @param {Object} obj The object in which to look for key.
* @param {?} key The key for which to check.
* @return {boolean} true If the map contains the key.
*/
goog.object.containsKey = function(obj, key) {
return obj !== null && key in obj;
};
/**
* Whether the object/map/hash contains the given value. This is O(n).
*
* @param {Object<K,V>} obj The object in which to look for val.
* @param {V} val The value for which to check.
* @return {boolean} true If the map contains the value.
* @template K,V
*/
goog.object.containsValue = function(obj, val) {
for (var key in obj) {
if (obj[key] == val) {
return true;
}
}
return false;
};
/**
* Searches an object for an element that satisfies the given condition and
* returns its key.
* @param {Object<K,V>} obj The object to search in.
* @param {function(this:T,V,string,Object<K,V>):boolean} f The
* function to call for every element. Takes 3 arguments (the value,
* the key and the object) and should return a boolean.
* @param {T=} opt_this An optional "this" context for the function.
* @return {string|undefined} The key of an element for which the function
* returns true or undefined if no such element is found.
* @template T,K,V
*/
goog.object.findKey = function(obj, f, opt_this) {
for (var key in obj) {
if (f.call(/** @type {?} */ (opt_this), obj[key], key, obj)) {
return key;
}
}
return undefined;
};
/**
* Searches an object for an element that satisfies the given condition and
* returns its value.
* @param {Object<K,V>} obj The object to search in.
* @param {function(this:T,V,string,Object<K,V>):boolean} f The function
* to call for every element. Takes 3 arguments (the value, the key
* and the object) and should return a boolean.
* @param {T=} opt_this An optional "this" context for the function.
* @return {V} The value of an element for which the function returns true or
* undefined if no such element is found.
* @template T,K,V
*/
goog.object.findValue = function(obj, f, opt_this) {
var key = goog.object.findKey(obj, f, opt_this);
return key && obj[key];
};
/**
* Whether the object/map/hash is empty.
*
* @param {Object} obj The object to test.
* @return {boolean} true if obj is empty.
*/
goog.object.isEmpty = function(obj) {
for (var key in obj) {
return false;
}
return true;
};
/**
* Removes all key value pairs from the object/map/hash.
*
* @param {Object} obj The object to clear.
*/
goog.object.clear = function(obj) {
for (var i in obj) {
delete obj[i];
}
};
/**
* Removes a key-value pair based on the key.
*
* @param {Object} obj The object from which to remove the key.
* @param {?} key The key to remove.
* @return {boolean} Whether an element was removed.
*/
goog.object.remove = function(obj, key) {
var rv;
if (rv = key in /** @type {!Object} */ (obj)) {
delete obj[key];
}
return rv;
};
/**
* Adds a key-value pair to the object. Throws an exception if the key is
* already in use. Use set if you want to change an existing pair.
*
* @param {Object<K,V>} obj The object to which to add the key-value pair.
* @param {string} key The key to add.
* @param {V} val The value to add.
* @template K,V
*/
goog.object.add = function(obj, key, val) {
if (obj !== null && key in obj) {
throw Error('The object already contains the key "' + key + '"');
}
goog.object.set(obj, key, val);
};
/**
* Returns the value for the given key.
*
* @param {Object<K,V>} obj The object from which to get the value.
* @param {string} key The key for which to get the value.
* @param {R=} opt_val The value to return if no item is found for the given
* key (default is undefined).
* @return {V|R|undefined} The value for the given key.
* @template K,V,R
*/
goog.object.get = function(obj, key, opt_val) {
if (obj !== null && key in obj) {
return obj[key];
}
return opt_val;
};
/**
* Adds a key-value pair to the object/map/hash.
*
* @param {Object<K,V>} obj The object to which to add the key-value pair.
* @param {string} key The key to add.
* @param {V} value The value to add.
* @template K,V
*/
goog.object.set = function(obj, key, value) {
obj[key] = value;
};
/**
* Adds a key-value pair to the object/map/hash if it doesn't exist yet.
*
* @param {Object<K,V>} obj The object to which to add the key-value pair.
* @param {string} key The key to add.
* @param {V} value The value to add if the key wasn't present.
* @return {V} The value of the entry at the end of the function.
* @template K,V
*/
goog.object.setIfUndefined = function(obj, key, value) {
return key in /** @type {!Object} */ (obj) ? obj[key] : (obj[key] = value);
};
/**
* Sets a key and value to an object if the key is not set. The value will be
* the return value of the given function. If the key already exists, the
* object will not be changed and the function will not be called (the function
* will be lazily evaluated -- only called if necessary).
*
* This function is particularly useful for use with a map used a as a cache.
*
* @param {!Object<K,V>} obj The object to which to add the key-value pair.
* @param {string} key The key to add.
* @param {function():V} f The value to add if the key wasn't present.
* @return {V} The value of the entry at the end of the function.
* @template K,V
*/
goog.object.setWithReturnValueIfNotSet = function(obj, key, f) {
if (key in obj) {
return obj[key];
}
var val = f();
obj[key] = val;
return val;
};
/**
* Compares two objects for equality using === on the values.
*
* @param {!Object<K,V>} a
* @param {!Object<K,V>} b
* @return {boolean}
* @template K,V
*/
goog.object.equals = function(a, b) {
for (var k in a) {
if (!(k in b) || a[k] !== b[k]) {
return false;
}
}
for (var k in b) {
if (!(k in a)) {
return false;
}
}
return true;
};
/**
* Returns a shallow clone of the object.
*
* @param {Object<K,V>} obj Object to clone.
* @return {!Object<K,V>} Clone of the input object.
* @template K,V
*/
goog.object.clone = function(obj) {
// We cannot use the prototype trick because a lot of methods depend on where
// the actual key is set.
var res = {};
for (var key in obj) {
res[key] = obj[key];
}
return res;
// We could also use goog.mixin but I wanted this to be independent from that.
};
/**
* Clones a value. The input may be an Object, Array, or basic type. Objects and
* arrays will be cloned recursively.
*
* WARNINGS:
* <code>goog.object.unsafeClone</code> does not detect reference loops. Objects
* that refer to themselves will cause infinite recursion.
*
* <code>goog.object.unsafeClone</code> is unaware of unique identifiers, and
* copies UIDs created by <code>getUid</code> into cloned results.
*
* @param {*} obj The value to clone.
* @return {*} A clone of the input value.
*/
goog.object.unsafeClone = function(obj) {
var type = goog.typeOf(obj);
if (type == 'object' || type == 'array') {
if (goog.isFunction(obj.clone)) {
return obj.clone();
}
var clone = type == 'array' ? [] : {};
for (var key in obj) {
clone[key] = goog.object.unsafeClone(obj[key]);
}
return clone;
}
return obj;
};
/**
* Returns a new object in which all the keys and values are interchanged
* (keys become values and values become keys). If multiple keys map to the
* same value, the chosen transposed value is implementation-dependent.
*
* @param {Object} obj The object to transpose.
* @return {!Object} The transposed object.
*/
goog.object.transpose = function(obj) {
var transposed = {};
for (var key in obj) {
transposed[obj[key]] = key;
}
return transposed;
};
/**
* The names of the fields that are defined on Object.prototype.
* @type {Array<string>}
* @private
*/
goog.object.PROTOTYPE_FIELDS_ = [
'constructor', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable',
'toLocaleString', 'toString', 'valueOf'
];
/**
* Extends an object with another object.
* This operates 'in-place'; it does not create a new Object.
*
* Example:
* var o = {};
* goog.object.extend(o, {a: 0, b: 1});
* o; // {a: 0, b: 1}
* goog.object.extend(o, {b: 2, c: 3});
* o; // {a: 0, b: 2, c: 3}
*
* @param {Object} target The object to modify. Existing properties will be
* overwritten if they are also present in one of the objects in
* {@code var_args}.
* @param {...Object} var_args The objects from which values will be copied.
*/
goog.object.extend = function(target, var_args) {
var key, source;
for (var i = 1; i < arguments.length; i++) {
source = arguments[i];
for (key in source) {
target[key] = source[key];
}
// For IE the for-in-loop does not contain any properties that are not
// enumerable on the prototype object (for example isPrototypeOf from
// Object.prototype) and it will also not include 'replace' on objects that
// extend String and change 'replace' (not that it is common for anyone to
// extend anything except Object).
for (var j = 0; j < goog.object.PROTOTYPE_FIELDS_.length; j++) {
key = goog.object.PROTOTYPE_FIELDS_[j];
if (Object.prototype.hasOwnProperty.call(source, key)) {
target[key] = source[key];
}
}
}
};
/**
* Creates a new object built from the key-value pairs provided as arguments.
* @param {...*} var_args If only one argument is provided and it is an array
* then this is used as the arguments, otherwise even arguments are used as
* the property names and odd arguments are used as the property values.
* @return {!Object} The new object.
* @throws {Error} If there are uneven number of arguments or there is only one
* non array argument.
*/
goog.object.create = function(var_args) {
var argLength = arguments.length;
if (argLength == 1 && goog.isArray(arguments[0])) {
return goog.object.create.apply(null, arguments[0]);
}
if (argLength % 2) {
throw Error('Uneven number of arguments');
}
var rv = {};
for (var i = 0; i < argLength; i += 2) {
rv[arguments[i]] = arguments[i + 1];
}
return rv;
};
/**
* Creates a new object where the property names come from the arguments but
* the value is always set to true
* @param {...*} var_args If only one argument is provided and it is an array
* then this is used as the arguments, otherwise the arguments are used
* as the property names.
* @return {!Object} The new object.
*/
goog.object.createSet = function(var_args) {
var argLength = arguments.length;
if (argLength == 1 && goog.isArray(arguments[0])) {
return goog.object.createSet.apply(null, arguments[0]);
}
var rv = {};
for (var i = 0; i < argLength; i++) {
rv[arguments[i]] = true;
}
return rv;
};
/**
* Creates an immutable view of the underlying object, if the browser
* supports immutable objects.
*
* In default mode, writes to this view will fail silently. In strict mode,
* they will throw an error.
*
* @param {!Object<K,V>} obj An object.
* @return {!Object<K,V>} An immutable view of that object, or the
* original object if this browser does not support immutables.
* @template K,V
*/
goog.object.createImmutableView = function(obj) {
var result = obj;
if (Object.isFrozen && !Object.isFrozen(obj)) {
result = Object.create(obj);
Object.freeze(result);
}
return result;
};
/**
* @param {!Object} obj An object.
* @return {boolean} Whether this is an immutable view of the object.
*/
goog.object.isImmutableView = function(obj) {
return !!Object.isFrozen && Object.isFrozen(obj);
};