The following is a changelog for JavaScript 1.8.5. This version was included in Firefox 4.
New features in JavaScript 1.8.5
New functions
| Function | Description |
|---|---|
Object.create() |
Creates a new object with the specified prototype object and properties. bug 492840 |
Object.defineProperty() |
Adds the named property described by a given descriptor to an object. |
Object.defineProperties() |
Adds the named properties described by the given descriptors to an object. |
Object.getOwnPropertyDescriptor() |
Returns a property descriptor for a named property on an object. bug 505587 |
Object.keys() |
Returns an array of all enumerable properties on an object. bug 307791 |
Object.getOwnPropertyNames() |
Returns an array of all enumerable and non-enumerable properties on an object. bug 518663 |
Object.preventExtensions() |
Prevents any extensions of an object. bug 492849 |
Object.isExtensible() |
Determine if extending of an object is allowed. bug 492849 |
Object.seal() |
Prevents other code from deleting properties of an object. bug 492845 |
Object.isSealed() |
Determine if an object is sealed. bug 492845 |
Object.freeze() |
Freezes an object: other code can't delete or change any properties. bug 492844 |
Object.isFrozen() |
Determine if an object was frozen. bug 492844 |
Array.isArray() |
Checks if a variable is an array. bug 510537 |
Date.prototype.toJSON() |
Returns a JSON format string for a Date object. |
Function.prototype.bind() |
Creates a new function that, when called, itself calls this function in the context provided (with a given sequence of arguments) bug 429507 |
New ECMAScript5 features
getandsetoperators now allows the identifier to be numeric or a string. bug 520696Function.apply()can accept any array-like object as the arguments list, instead of only true arrays.- strict mode support
Array.toString()now works even on non-arrays by either returning the result of calling itsjoin()method if one is available or by calling itstoString()method.
Other standardization work
Various non-standard syntaxes for defining getters and setters have been removed; ECMAScript 5 defined syntax has not been changed. These were all pretty esoteric and rarely used; if this affects you, see this blog post for details.
New objects
| Object | Description |
|---|---|
Proxy |
Offers support for creating Object and Function proxies that enable meta-programming in JavaScript. |
Changed functionality in JavaScript 1.8.5
- ISO 8601 support in
Date:The Date object's parse() method now supports simple ISO 8601 format date strings. - Global objects made read only: The
NaN,Infinity, andundefinedglobal objects have been made read only, per the ECMAScript 5 specification. obj.__parent__andobj.__count__become obsolete. Some information about why: SpiderMonkey change du jour: the special __parent__ property has been removed bug 551529 & bug 552560.- Trailing commas no longer accepted in
JSON.parse().