获得未知数量的论据后，将其传递给另一个函数

Question

As a follow up to the below question, I have a need to send the arguments I received to another function.

Pass unknown number of arguments into javascript function

For example:

myObj.RunCall("callName", 1,2,3,4,5);
myObj.RunCall("anotherCall", 1);
myObj.RunCall("lastCall");

where

runCall = function(methodName)
{
    // do something clever with methodName here, consider it 'used up'
    console.log(methodName);

    // using 'arguments' here will give me all the 'extra' args
    var x = arguments.length;

    // somehow extract all the extra args into local vars?
    // assume there were 4 (there could be 0-100)

    otherObj.DoIt(arg1, arg2, arg3, arg4);     // here i need to send those "extra" args onwards
}

Answer 1

The .apply() method lets you call a function with arguments that are in an array. So:

otherObj.DoIt(1,2,3);
// is equivalent to
otherObj.DoIt.apply(otherObj, [1,2,3]);

(The first argument to .apply() is the object that is to become this within the function you are calling.)

So you just need to create an array with the values from arguments , which you can get using .slice() to skip the first one:

 var runCall = function(methodName) { console.log("In runCall() - methodName is " + methodName); var extras = [].slice.call(arguments, 1); otherObj.DoIt.apply(otherObj, extras); } // simple `otherObj.DoIt() for demo purposes: var otherObj = { DoIt: function() { console.log("In DoIt()", arguments); }} runCall("someMethod", 1,2,3); runCall("someMethod", 'a', 'b'); runCall("someMethod");