How can I declare a variable as a function as well as assign values to it

March 1, 2021 by admin

I tried this:

 var fun = function(){ console.log("booyah"} , {
  hell: function(){
    console.log("hello");
  },
  boy: ()=>{
    alert("blah");
  }
};
fun.boy();

I want that first I call fun function and then Access functions I have stored as objects. But I am getting errors . How can I fix it? Or is there any other way to do that?
Please help.

28 thoughts on “How can I declare a variable as a function as well as assign values to it”

Check the below code, reference taken from Can you create functions with custom prototypes in JavaScript?

function MyFun() {
    if (!this || this==window) {
        return new MyFun();
    }

    var f = function() {
        return "thanks for calling!";
    }
    f.__proto__ = MyFun.prototype;
    f.constructor = MyFun;

    return f;
}

MyFun.prototype = {
    foo: function() {
        return "foo:" + this();
    },
    __proto__: Function.prototype
};

var f = new MyFun();
alert("proto method:"+f.foo()); // try our prototype methods
alert("function method:"+f.call()); // try standard function methods
alert("function call:"+f()); // try use as a function
alert('typeof:' + typeof f); // "function", not "object". No way around it in current js versions
alert('is MyFun:' + (f instanceof MyFun)); // true
alert('is Function:' + (f instanceof Function)); // true

You can achieve this kind of result by editing the prototype of the function.

Example:

function foo() {
        const something = 'the thing';
    
        return something;
    }
    
    const customPrototype = {
        greeting: (name) => {
            const greetingTemplate = `Hello ${name}`;
    
            return greetingTemplate;
        },
    
        randomNumber: () => {
            return Math.random();
        },
    };
    
    // Extending prototype to access our custom prototype functions
    Object.assign(foo, customPrototype);
    
    
    console.log(foo()); // the thing
    console.log(foo.greeting('People')); // Hello People
    console.log(foo.randomNumber()); // 0.26138311987993545
    // Default prototype functions are working as well
    console.log(foo.toString()); // [object Function]

EDIT: Thanks to @Bergi for correcting me!