The Javascript handler isExtensible() method traps for Object.isExtensible(). It is commonly used for logging or auditing calls.
Syntax:
isExtensible: function(target)
Parameters:
target: It represents the target object.
Return:
Boolean.
Example:
<!DOCTYPE html> <html> <body> <script> const handler={ too:1 } const extent = new Proxy(handler, { isExtensible: function(a) { document.writeln('HELLO WORLD! : '); return true; }}); document.writeln(Object.isExtensible(extent)); </script> </body> </html>