Can a JavaScript function return itself?
Can I write a function that returns iteself?
I was reading some description on closures - see Example 6 - where a function was returning a function, so you could call func()();
as valid JavaScript.
So I was wondering could a function return itself in such a way that you could ch开发者_JAVA百科ain it to itself indefinitely like this:
func(arg)(other_arg)()(blah);
Using arguments
object, callee or caller?
There are 2-3 ways. One is, as you say, is to use arguments.callee
. It might be the only way if you're dealing with an anonymous function that's not stored assigned to a variable somewhere (that you know of):
(function() {
return arguments.callee;
})()()()().... ;
The 2nd is to use the function's name
function namedFunc() {
return namedFunc;
}
namedFunc()()()().... ;
And the last one is to use an anonymous function assigned to a variable, but you have to know the variable, so in that case I see no reason, why you can't just give the function a name, and use the method above
var storedFunc = function() {
return storedFunc;
};
storedFunc()()()().... ;
They're all functionally identical, but callee
is the simplest.
Edit: And I agree with SLaks; I can't recommend it either
Yes.
Just return arguments.callee;
However, this is likely to result in very confusing code; I do not recommend it.
You can do what you want as following:
// Do definition and execution at the same time.
var someFunction = (function someFunction() {
// do stuff
return someFunction
})();
console.log(someFunction)
arguments.callee is not supported in JavaScript strict mode.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode
Even sorter that all the above is:
f=()=>f
There is a simple way to achieve this doing the following:
let intArr = [];
function mul(x){
if(!x){
return intArr.reduce((prev, curr) => prev * curr)
}
intArr.push(x);
return mul;
}
console.log(mul(2)(4)(2)()); => outputs 16
It is also possible just to return the argument the self invokable function like
console.log( (function(a) { return a; })(1) ); // returns 1
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