Object
Related Docs:
class Object
| package js
The Object.create() method creates a new object with the specified prototype object and properties.
The Object.create() method creates a new object with the specified prototype object and properties.
MDN
The Object.defineProperties() method defines new or modifies existing properties directly on an object, returning the object.
The Object.defineProperties() method defines new or modifies existing properties directly on an object, returning the object.
MDN
The Object.defineProperty() method defines a new property directly on an object, or modifies an existing property on an object, and returns the object.
The Object.defineProperty() method defines a new property directly on an object, or modifies an existing property on an object, and returns the object.
This method allows precise addition to or modification of a property on an object. Normal property addition through assignment creates properties which show up during property enumeration (for...in loop or Object.keys method), whose values may be changed, and which may be deleted. This method allows these extra details to be changed from their defaults.
Property descriptors present in objects come in two main flavors: data descriptors and accessor descriptors. A data descriptor is a property that has a value, which may or may not be writable. An accessor descriptor is a property described by a getter-setter pair of functions. A descriptor must be one of these two flavors; it cannot be both.
MDN
The Object.freeze() method freezes an object: that is, prevents new properties from being added to it; prevents existing properties from being removed; and prevents existing properties, or their enumerability, configurability, or writability, from being changed.
The Object.freeze() method freezes an object: that is, prevents new properties from being added to it; prevents existing properties from being removed; and prevents existing properties, or their enumerability, configurability, or writability, from being changed. In essence the object is made effectively immutable. The method returns the object being frozen.
MDN
The Object.getOwnPropertyDescriptor() method returns a property descriptor for an own property (that is, one directly present on an object, not present by dint of being along an object's prototype chain) of a given object.
The Object.getOwnPropertyDescriptor() method returns a property descriptor for an own property (that is, one directly present on an object, not present by dint of being along an object's prototype chain) of a given object.
MDN
Object.getOwnPropertyNames returns an array whose elements are strings corresponding to the enumerable and non-enumerable properties found directly upon obj.
Object.getOwnPropertyNames returns an array whose elements are strings corresponding to the enumerable and non-enumerable properties found directly upon obj. The ordering of the enumerable properties in the array is consistent with the ordering exposed by a for...in loop (or by Object.keys) over the properties of the object. The ordering of the non-enumerable properties in the array, and among the enumerable properties, is not defined.
MDN
The Object.getPrototypeOf() method returns the prototype (i.e.
The Object.getPrototypeOf() method returns the prototype (i.e. the
internal Prototype) of the specified object.
MDN
Tests whether this object has the specified property as a direct property.
Tests whether this object has the specified property as a direct property.
Unlike js.Object.hasProperty, this method does not check down the object's prototype chain.
MDN
Tests whether the object has a property on itself or in its prototype chain.
Tests whether the object has a property on itself or in its prototype
chain. This method is the equivalent of p in o in JavaScript.
Determines if extending of an object is allowed
Determines if extending of an object is allowed
Objects are extensible by default: they can have new properties added to them, and (in engines that support proto their proto property) can be modified. An object can be marked as non-extensible using Object.preventExtensions, Object.seal, or Object.freeze
MDN
The Object.isFrozen() determines if an object is frozen.
The Object.isFrozen() determines if an object is frozen.
An object is frozen if and only if it is not extensible, all its properties are non-configurable, and all its data properties (that is, properties which are not accessor properties with getter or setter components) are non-writable.
MDN
Tests whether this object is in the prototype chain of another object.
Tests whether this object is in the prototype chain of another object.
Returns true if the object is sealed, otherwise false.
Returns true if the object is sealed, otherwise false. An object is sealed if it is not extensible and if all its properties are non-configurable and therefore not removable (but not necessarily non-writable).
MDN
The Object.keys() method returns an array of a given object's own enumerable properties, in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).
The Object.keys() method returns an array of a given object's own enumerable properties, in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).
MDN
The Object.preventExtensions() method prevents new properties from ever being added to an object (i.e.
The Object.preventExtensions() method prevents new properties from ever being added to an object (i.e. prevents future extensions to the object).
An object is extensible if new properties can be added to it. preventExtensions marks an object as no longer extensible, so that it will never have properties beyond the ones it had at the time it was marked as non-extensible. Note that the properties of a non-extensible object, in general, may still be deleted. Attempting to add new properties to a non-extensible object will fail, either silently or by throwing a TypeError (most commonly, but not exclusively, when in strict mode).
Object.preventExtensions only prevents addition of own properties. Properties can still be added to the object prototype. However, calling Object.preventExtensions on an object will also prevent extensions on its proto property.
MDN
Returns the names of all the enumerable properties of this object, including properties in its prototype chain.
Returns the names of all the enumerable properties of this object, including properties in its prototype chain.
This method returns the same set of names that would be enumerated by a for-in loop in JavaScript, but not necessarily in the same order.
If the underlying implementation guarantees an order for for-in loops, then this is guaranteed to be consistent with keys, in the sense that the list returned by keys is a sublist of the list returned by this method (not just a subset).
Tests whether the specified property in an object can be enumerated by a call to js.Object.properties, with the exception of properties inherited through the prototype chain.
Tests whether the specified property in an object can be enumerated by a call to js.Object.properties, with the exception of properties inherited through the prototype chain. If the object does not have the specified property, this method returns false.
MDN
The Object.seal() method seals an object, preventing new properties from being added to it and marking all existing properties as non-configurable.
The Object.seal() method seals an object, preventing new properties from being added to it and marking all existing properties as non-configurable. Values of present properties can still be changed as long as they are writable.
MDN
The top-level
ObjectJavaScript object.