CODEWITHSUNDEEP
javascriptoverloading
Cem Frt
Cem Frt

Reputation: 31

Javascript best & fast way for function overloading

I wrote the following code for overloading functions in Javascript. This code can run slowly on large projects. Are there other ways to implement overloading functions in Javascript? Any other faster and more practical way?

(() => {
  //array that store functions
    var Funcs = []
     /**
     * @param {function} f overload function
     * @param {string} fname overload function name
   * @param {parameters} vtypes function parameters type descriptor (number,string,object....etc
     */
    overloadFunction = function(f, fname, ...vtypes) {
        var k,l, n = false;
        if (!Funcs.hasOwnProperty(fname)) Funcs[fname] = [];
        Funcs[fname].push([f, vtypes?vtypes: 0 ]);
        window[fname] = function() {
            for (k = 0; k < Funcs[fname].length; k++)
                if (arguments.length == Funcs[fname][k][0].length) {
                    n=true;
                    if (Funcs[fname][k][1]!=0)
                    for(i=0;i<arguments.length;i++)
                    {
                        if(typeof arguments[i]!=Funcs[fname][k][1][i])
                        {
                            n=false;
                        }
                    }
                    if(n) return Funcs[fname][k][0].apply(this, arguments);
                }
        }
    }
})();

//First sum function definition with parameter type descriptors
overloadFunction((a,b)=>{return a+b},"sum","number","number")
//Second sum function definition with parameter with parameter type descriptors
overloadFunction((a,b)=>{return a+" "+b},"sum","string","string")
//Third sum function definition (not need parameter type descriptors,because no other functions with the same number of parameters
overloadFunction((a,b,c)=>{return a+b+c},"sum")

//call first function
console.log(sum(4,2));//return 6
//call second function
console.log(sum("4","2"));//return "4 2"
//call third function
console.log(sum(3,2,5));//return 10
//ETC...

Upvotes: 1

Views: 1634

Answers (1)

PartialFlavor_55KP
PartialFlavor_55KP

Reputation: 157

The concept overload is to avoid a function with infinite parameters. That is the opposite of your pattern. A function should ideally have a handful of parameters. An overloaded function passes varied parameters within the overloaded parameter.

function overload(fname, arr=[]){
 let sum = 0;
 for(let i=0; i<arr.length; i++){
  sum += arr[i];
 }
 return fname + sum;
}

overload("Juan", [1]);

As such, arr isn't considered overloaded, it's of indeterminate length. But if instead of arr, you had obj, you could pass any number of types or values indiscriminately.

function overload(fname, obj={}){
 if(obj.arr){}
 if(obj.f){}
}

overload("Juan", {"arr":[1], "f":true, "infinite":-Infinity});

This overloaded parameter would be ideal for data with questionable scope or origin.

Upvotes: 1

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