像某些函数一样的JavaScript函数调用（“ Hi”）（“ Hello”）（“ How”）

Question

Please have a look at this code. I need to show a alert message "mikä on elämän tarkoitus?" using this code

window["mikä"]("on")("elämän")("tarkoitus")("?"); 

I need to write a function or piece of code that will show that alert message when I will execute that code.

I have written a function like this:

window["mikä"] = function(str){
alert(str);
}

which works when I call window"mikä" but if I add more like below in console I see a type error.

 window["mikä"]("on")("Hello")("How"); 

My question is would it be valid way to call like below as there is multiple function signs?

window["mikä"]("on")("elämän")("tarkoitus")("?") 

Answer 1

To achieve the functionality you are looking for one way is to write a function which returns a function which returns a function as the others mentioned. That works fine if the number of functions is known before hand. Another way is to use a functional programming technique called currying , which is

the technique of translating the evaluation of a function that takes multiple arguments (or a tuple of arguments) into evaluating a sequence of functions, each with a single argument (partial application).

You can write your own curry function like this:

function curry(func, args_) {
    var self = this;

    self.args = args_ || [];

    return function() {
        var extended_args = [].concat(self.args).concat(Array.slice(arguments));

        if(extended_args.length >= func.length)
            return func.apply(this, extended_args);

        return new curry(func, extended_args);
    };
}
var funcName = "mikä";
window[funcName] = curry(functionstr1, str2, str3, str4) {
    alert(funcName + ' ' + str1 + ' ' + str2 + ' ' + str3 + str4);    
});
window["mikä"]("on")("elämän")("tarkoitus")("?");

Here are some resources which can help you if you are interested in learning more about currying / functional programming in JS.

http://kukuruku.co/hub/javascript/an-interesting-task-for-an-interview-currying-and-partial-applicationof-a-function http://tech.pro/tutorial/2011/functional-javascript-part-4-function-currying Reginald Braithwaite's talk in NDC Oslo

Answer 2

You want the return value to be a function as well, so that additional calls on the return value will call the same function. Just add this

window["mikä"] = function(str){
  alert(str);
  return window["mikä"];
}

EDIT: Misread your question, this will make multiple alert messages. Sorry.

Answer 3

You probably want to nest the function calls

 window["mikä"] = function(s1){ return function(s2) { return function(s3) { alert(s1 + ' ' + s2 + ' ' + s3); } } } window["mikä"]("on")("elämän")("tarkoitus")("?"); 

As for getting the function name inside the function, there's really no good way to do that, and it should be avoided.