JavaScript 1.8.5 is the version of JavaScript included in Firefox 4.
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.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. |
Changes to global objects
Additional Changes
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()
JavaScript (SpiderMonkey) API changes
Note: Locale callbacks (as specified in the JSLocaleCallbacks structure) should not free the memory buffer passed to them; this buffer is managed by the SpiderMonkey runtime.
The JS_NewString() function was removed in SpiderMonkey 1.8.5. Use JS_NewStringCopyN() instead.
