/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Utilities for manipulating objects/maps/hashes.
*/
goog.provide('goog.object');
(function(exports) {
/**
* 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.
* @return {void}
* @template T,K,V
*/
function forEach(obj, f, opt_obj) {
for (const 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
*/
function filter(obj, f, opt_obj) {
const res = {};
for (const 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
*/
function map(obj, f, opt_obj) {
const res = {};
for (const 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
*/
function some(obj, f, opt_obj) {
for (const 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
*/
function every(obj, f, opt_obj) {
for (const 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.
*/
function getCount(obj) {
let rv = 0;
for (const 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.
*/
function getAnyKey(obj) {
for (const 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
*/
function getAnyValue(obj) {
for (const key in obj) {
return obj[key];
}
}
/**
* Whether the object/hash/map contains the given object as a value.
* An alias for 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
*/
function contains(obj, val) {
return 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
*/
function getValues(obj) {
const res = [];
let i = 0;
for (const 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.
*/
function getKeys(obj) {
const res = [];
let i = 0;
for (const 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 in the
* current object is null or undefined, returns undefined.
*/
function getValueByKeys(obj, var_args) {
const isArrayLike = goog.isArrayLike(var_args);
const keys = isArrayLike ?
/** @type {!IArrayLike<number|string>} */ (var_args) :
arguments;
// Start with the 2nd parameter for the variable parameters syntax.
for (let i = isArrayLike ? 0 : 1; i < keys.length; i++) {
if (obj == null) return undefined;
obj = obj[keys[i]];
}
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.
*/
function containsKey(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
*/
function containsValue(obj, val) {
for (const 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=} thisObj 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
*/
function findKey(obj, f, thisObj = undefined) {
for (const key in obj) {
if (f.call(/** @type {?} */ (thisObj), 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=} thisObj 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
*/
function findValue(obj, f, thisObj = undefined) {
const key = findKey(obj, f, thisObj);
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.
*/
function isEmpty(obj) {
for (const key in obj) {
return false;
}
return true;
}
/**
* Removes all key value pairs from the object/map/hash.
* @param {?Object} obj The object to clear.
* @return {void}
*/
function clear(obj) {
for (const 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.
*/
function remove(obj, key) {
let 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.
* @return {void}
* @template K,V
*/
function add(obj, key, val) {
if (obj !== null && key in obj) {
throw new Error(`The object already contains the key "${key}"`);
}
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=} 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
*/
function get(obj, key, val = undefined) {
if (obj !== null && key in obj) {
return obj[key];
}
return 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
* @return {void}
*/
function set(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
*/
function setIfUndefined(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 when used with an `Object` which is
* acting 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
*/
function setWithReturnValueIfNotSet(obj, key, f) {
if (key in obj) {
return obj[key];
}
const 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
*/
function equals(a, b) {
for (const k in a) {
if (!(k in b) || a[k] !== b[k]) {
return false;
}
}
for (const 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
*/
function clone(obj) {
const res = {};
for (const key in obj) {
res[key] = obj[key];
}
return res;
}
/**
* Clones a value. The input may be an Object, Array, or basic type. Objects and
* arrays will be cloned recursively.
* WARNINGS:
* <code>unsafeClone</code> does not detect reference loops. Objects
* that refer to themselves will cause infinite recursion.
* <code>unsafeClone</code> is unaware of unique identifiers, and
* copies UIDs created by <code>getUid</code> into cloned results.
* @param {T} obj The value to clone.
* @return {T} A clone of the input value.
* @template T
*/
function unsafeClone(obj) {
if (!obj || typeof obj !== 'object') return obj;
if (typeof obj.clone === 'function') return obj.clone();
if (typeof Map !== 'undefined' && obj instanceof Map) {
return new Map(obj);
} else if (typeof Set !== 'undefined' && obj instanceof Set) {
return new Set(obj);
} else if (obj instanceof Date) {
return new Date(obj.getTime());
}
const clone = Array.isArray(obj) ? [] :
typeof ArrayBuffer === 'function' &&
typeof ArrayBuffer.isView === 'function' && ArrayBuffer.isView(obj) &&
!(obj instanceof DataView) ?
new obj.constructor(obj.length) :
{};
for (const key in obj) {
clone[key] = unsafeClone(obj[key]);
}
return clone;
}
/**
* 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.
*/
function transpose(obj) {
const transposed = {};
for (const key in obj) {
transposed[obj[key]] = key;
}
return transposed;
}
/**
* The names of the fields that are defined on Object.prototype.
* @type {!Array<string>}
*/
const 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 = {};
* extend(o, {a: 0, b: 1});
* o; // {a: 0, b: 1}
* 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 `var_args`.
* @param {...(?Object|undefined)} var_args The objects from which values
* will be copied.
* @return {void}
* @deprecated Prefer Object.assign
*/
function extend(target, var_args) {
let key;
let source;
for (let 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 (let j = 0; j < PROTOTYPE_FIELDS.length; j++) {
key = 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.
*/
function create(var_args) {
const argLength = arguments.length;
if (argLength == 1 && Array.isArray(arguments[0])) {
return create.apply(null, arguments[0]);
}
if (argLength % 2) {
throw new Error('Uneven number of arguments');
}
const rv = {};
for (let 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.
*/
function createSet(var_args) {
const argLength = arguments.length;
if (argLength == 1 && Array.isArray(arguments[0])) {
return createSet.apply(null, arguments[0]);
}
const rv = {};
for (let 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
*/
function createImmutableView(obj) {
let 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.
*/
function isImmutableView(obj) {
return !!Object.isFrozen && Object.isFrozen(obj);
}
/**
* Get all properties names on a given Object regardless of enumerability.
* <p> If the browser does not support `Object.getOwnPropertyNames` nor
* `Object.getPrototypeOf` then this is equivalent to using
* `getKeys`
* @param {?Object} obj The object to get the properties of.
* @param {boolean=} includeObjectPrototype Whether properties defined on
* `Object.prototype` should be included in the result.
* @param {boolean=} includeFunctionPrototype Whether properties defined on
* `Function.prototype` should be included in the result.
* @return {!Array<string>}
* @public
*/
function getAllPropertyNames(
obj, includeObjectPrototype = undefined,
includeFunctionPrototype = undefined) {
if (!obj) {
return [];
}
// Naively use a for..in loop to get the property names if the browser doesn't
// support any other APIs for getting it.
if (!Object.getOwnPropertyNames || !Object.getPrototypeOf) {
return getKeys(obj);
}
const visitedSet = {};
// Traverse the prototype chain and add all properties to the visited set.
let proto = obj;
while (proto && (proto !== Object.prototype || !!includeObjectPrototype) &&
(proto !== Function.prototype || !!includeFunctionPrototype)) {
const names = Object.getOwnPropertyNames(proto);
for (let i = 0; i < names.length; i++) {
visitedSet[names[i]] = true;
}
proto = Object.getPrototypeOf(proto);
}
return getKeys(visitedSet);
}
/**
* Given a ES5 or ES6 class reference, return its super class / super
* constructor.
* This should be used in rare cases where you need to walk up the inheritance
* tree (this is generally a bad idea). But this work with ES5 and ES6 classes,
* unlike relying on the superClass_ property.
* Note: To start walking up the hierarchy from an instance call this with its
* `constructor` property; e.g. `getSuperClass(instance.constructor)`.
* @param {function(new: ?)} constructor
* @return {?Object}
*/
function getSuperClass(constructor) {
const proto = Object.getPrototypeOf(constructor.prototype);
return proto && proto.constructor;
}
exports = {
add,
clear,
clone,
contains,
containsKey,
containsValue,
create,
createImmutableView,
createSet,
equals,
every,
extend,
filter,
findKey,
findValue,
forEach,
get,
getAllPropertyNames,
getAnyKey,
getAnyValue,
getCount,
getKeys,
getSuperClass,
getValueByKeys,
getValues,
isEmpty,
isImmutableView,
map,
remove,
set,
setIfUndefined,
setWithReturnValueIfNotSet,
some,
transpose,
unsafeClone,
};
})(goog.object);
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