JavaScript preventExtensions() method
The Javascript handler preventExtensions() method traps the Object.preventExtensions method. New properties can not be added to the object when extensions are prevented. Syntax: preventExtensions: function(target) Parameters: target: It represents the target object. Return: Boolean. Example: <!DOCTYPE html> <html> <body> <script> const handler = new Proxy({}, { preventExtensions: function(a) { Object.preventExtensions(a); return !Object.isExtensible(a); }}); document.writeln(‘Value: ‘); … Read more