The handler.apply function is utilized to intercept a function call. The value that the apply trap returns will also serve as the outcome of a function invocation via a proxy.
Syntax
Example
apply: function(target, thisArg, argumentsList)
Parameters
target : The target object.
thisArg : thisArg use for the call.
argumentsList: This refers to the collection of parameters utilized during the invocation.
Return value
This method can return any value.
Browser Support
| Chrome | 49 |
|---|---|
Edge |
12 |
| Firefox | 18 |
| Opera | 36 |
Example 1
Example
var o = function(arg1, arg2) {
document.writeln('proxy value(' + arg1 + ', ' + arg2 + ')');
};
var proxy = new Proxy(o, {
apply: function(target, thisArg, parameters) {
document.writeln('First exam..');
document.writeln("</br>");
return target.apply(thisArg, parameters);
}
});
proxy('23', '54');
Output:
Output
First exam..
proxy value(23, 54)
Example 2
Example
var str = function(arg1, arg2) {
document.writeln('in x(' + arg1 + ', ' + arg2 + ')');
};
var proxy = new Proxy(str, {
apply: function(target, thisArg, parameters) {
document.writeln('in apply');
document.writeln("<br/>");
return target.apply(thisArg, parameters);
}
});
proxy('direct1', 'direct2');
proxy.apply(null, ['add', 'add']);
proxy.call(null, 'string', 'string');
Output:
Output
in apply
in x(direct1, direct2) in apply
in x(add, add) in apply
in x(string, string)
Example 3
Example
function p (a)
{
return a ;
}
var q = {
apply: function(target, thisArg, argumentsList) {
return target(argumentsList[0], argumentsList[1])*2;
}};
var pro = new Proxy(p, q);
document.writeln(p(56));
document.writeln("<br/>");
document.writeln(pro(34));
Output:
Output
56
68
