JavaScript handler.preventExtensions() Method18 Mar 2025 | 1 min read The handler.preventExtensions() method is used to trap the Object.preventExtensions method. When extensions are prevented on an object, new properties can't be added. SyntaxParameterstarget: The target object. Return valueReturn a Boolean value. Browser Support
Example 1Output: true Example 2Output: true [object Object] false Example 3Output: false false Next TopicJavaScript handler |
methods Let's see the list of methods. methods apply() construct() defineProperty() deleteProperty() get() getOwnPropertyDescriptor() getPrototypeOf() has() isExtensible() ownKeys() entExtensions() set() setPrototypeOf() TopicJavaScript handler ...
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JavaScript handler. Method The handler. method is a trap for Object.. It exists as an own property of the target object and the target object is not extensible. Syntax getOwnPropertyDescriptor: function(target, prop) Parameters Target: The target object. Prop: The name of the property whose description should be retrieved. Return value This method returns...
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JavaScript handler. Method The handler. method is used to trap for a function call. The value returned by the apply trap is also going to be used as the result of a function call through a proxy. Syntax apply: function(target, thisArg, argumentsList) Parameters target: The target object. thisArg: thisArg use for...
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JavaScript handler. Method The handler. method can define the new properties. It can also modify the existing properties directly on an object. It is trap for Object.defineProper(). This method can be used in two situations. When we wanted to ensure cross-browser support of getters and setters. Whenever we...
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JavaScript handler. Method The handler.setPrototypeOf method returns a Boolean value true if [[Prototype]] was successfully changed. Otherwise, it will return false. It is a trap for Object.. Syntax setPrototypeOf: function(target, prototype) Parameters target: The target object. prototype: The object's new prototype or null. Return value Return a Boolean type value. Browser Support Chrome Compatibility unknown Edge Compatibility unknown Firefox 49 Opera Compatibility...
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JavaScript handler. Method The handler. method is a trap for the internal method. If target is not extensible, then this method returns the same value as Object.getPrototypeOf(target). Syntax getPrototypeOf(target) Parameters target: The target object. Return value This method returns an object or null. Browser Support Chrome NO Edge NO Firefox 49 Opera NO Example 1 const obj = {}; const proto = {}; const hag...
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JavaScript handler. Method The handler. method a trap for Object.. We can be mostly used for logging or auditing calls to Object.isExtensible (determine if an object is "extensible"). Syntax isExtensible: function(target) Parameters target: The target object. Return value Return a Boolean value. Browser Support Chrome Compatibility unknown Edge Compatibility unknown Firefox 31 Opera Compatibility unknown Example 1 var x = { foo: 1...
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JavaScript handler. Method The handler. method of JavaScript is used to return an enumerable object. This method is a trap for Reflect.. Syntax ownKeys: function(target) Parameters target: The target object. Return value Return an enumerable object. Browser Support Chrome 49 Edge 12 Firefox 18 Opera 36 Example 1 <script> var proxy1 = new Proxy({}, { ownKeys: function(target) { document.writeln(" Use handler....
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JavaScript handler. Method The handler. method used to "hide" any property you want. It's a trap for an operator. It returns the Boolean value true if you want the property to be accessed, otherwise false If the key is present or not in the original object. Syntax has:...
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JavaScript handler. Method The handler.get method is a trap for getting a property value. This method takes 3 arguments. Syntax get: function(target, property, receiver) Parameters Target: The target object. Property: Name of the property to get. Receiver: The proxy or an object that inherits from the proxy. Return value This method can return any...
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