Array of functions in javascript

Question

I have some JavaScript functions in each page that I call them after jQuery is loaded.
The function in Questions.aspx page is afterQuestions(), the function in Default.aspx is afterDefault() and so on ....

In my master page I am calling them like:

if(typeof(afterQuestion) == 'function') afterQuestions();
if(typeof(afterDefault) == 'function') afterDefault();

As the number of functions grew, I tried something like:

var _fs = [After, AfterDefault,  afterSettings, afterQuestions];
for (var i = 0; i < _fs.length; i++) if (typeof (_fs[i]) == "function")  _fs[i]();

But it doesn't work this way. Can you please help me how can I create an Array of functions and call them?

Edit: I think nobody had read the question well to see that the all functions won't exist at the same time and that was the problem creating the array. I solved it by adding created functions to a global array and the looping and excuting functions in that array

possible duplicate of [How can I check if a javascript variable is function type?](http://stackoverflow.com/questions/5999998/how-can-i-check-if-a-javascript-variable-is-function-type) — Mr. Polywhirl, Jul 02 '15 at 13:51
This works fine check out this fiddle https://jsfiddle.net/u0bprym2/ there must be something else that you haven't posted here... — brso05, Jul 02 '15 at 13:52
well the functions are not called now but was working perfectly before. I don't know whether there is a problem with my array or the way I'm calling the functions — Ashkan Mobayen Khiabani, Jul 02 '15 at 13:53
Cannot reproduce: http://jsbin.com/xurokejivi/1/edit?js,console — Quentin, Jul 02 '15 at 13:53
well if the function is not defined, than it will throw an error.... — epascarello, Jul 02 '15 at 13:55
So many different close votes. It's really just a matter of the problem not being reproducible. — Cerbrus, Jul 02 '15 at 13:57
THE PROBLEM IS! And I was posted the solution and you closed it....grrr — epascarello, Jul 02 '15 at 13:57
the logic behind the check looks fine I think one of the function does not exist in the page or you are mistyping it. Check in the console that you can reach every function. — Onur Topal, Jul 02 '15 at 13:57
What do you mean by " it doesn't work this way", what is the behavior?. — borja gómez, Jul 02 '15 at 13:57
well I actually found the problem. As I told each of those functions are in a separate page and I was just checking each function and calling it if exists. It works perfect @brso05 's fiddle (jsfiddle.net/u0bprym2) because all the functions exists there. but creating the array fails if one of the functions doesn't exist. you can try by removing one of the functions in the fiddle — Ashkan Mobayen Khiabani, Jul 02 '15 at 14:33
@brso05 just look at the begining of the question: **I have some JavaScript functions in each page that I call them after jQuery is loaded. The function in Questions.aspx page is afterQuestions() and in my master page I was calling them like:** well English is not my mother tongue and I might not have expressed my problem very well. — Ashkan Mobayen Khiabani, Jul 02 '15 at 14:45
@AshkanMobayenKhiabani it's alright man no worries glad you got it working! — brso05, Jul 02 '15 at 14:48

epascarello · Accepted Answer · 2015-07-02T15:29:25.220

1

If the function is not defined, you will get a JavaScript error since you are trying to reference a variable that is not defined. The type of check in your original code gets around that issue.

Your best bet is to namespace the functions into an object and use dot notation.

var methods = {
    After : function () {console.log("After"); },
    AfterDefault : function () {console.log("AfterDefault"); },
    afterSettings : function () {console.log("afterSettings"); }
};

var _fs = [methods.After, methods.AfterDefault,  methods.afterSettings, methods.afterQuestions];
for (var i = 0; i < _fs.length; i++) {
    if (typeof (_fs[i]) == "function")  {
       _fs[i]();
    }
}

Now when you want to register the methods you can just add to the methods object.

methods = methods || {};
methods.afterSettings = function () {  console.log("added this in"); };

Now if the method is not defined the namespace will return undefined and the check will not error out.

edited Jul 02 '15 at 15:29

answered Jul 02 '15 at 15:17

epascarello

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Thanks for the downvote! This is the answer since I talked with the OP and worked on the problem since you folks who closed it did not read the question. – epascarello Jul 02 '15 at 15:26
but the problem is that each function is in a separate page I can not define them all in one namespace. I created global array in the head of my master page like : `var afterFuncs = [];` and in every page when I create a function I'm adding it to this array: `var a = function afterDefault(){...} afterFuncs.push(a);` now at the bottom of my master page I just call them all in a loop and even don't need to check if they exist. `for(var i=0;i – Ashkan Mobayen Khiabani Jul 02 '15 at 15:27
@AshkanMobayenKhiabani If order of them being called does not matter than that is a okay solution. Unless it is guaranteed that the way you push them to the array is how you want them to be called. You can do it all in one namespace if the namespace is global. You just add the method to the object as I noted above. – epascarello Jul 02 '15 at 15:30
Thanks a lot. your answer does not exactly match with my code and thats because you don't have all the codes. but your answer helped me find the error and also give me the clue to solve it. Thanks again dude – Ashkan Mobayen Khiabani Jul 02 '15 at 15:32
hey people! do you have a problem? why do you keep down voting the correct answer that actually works? – Ashkan Mobayen Khiabani Jul 02 '15 at 15:35

Array of functions in javascript

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