JS Functions

links: JS MOC

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Function Declaration vs Expression

Inputs

JS Functions can receive parameters from zero to upward

function greeting(myName) {
    console.log(`Hello, ${ myName }!`);
}

greeting("Subramanya")

Return

JS Functions can return values using return keyword

function greeting(myName) {
    return `Hello, ${ myName }!`;
}

var msg = greeting("Subramanya")

console.log(msg) // Hello Subramanya

You can only return a single value

Function Declaration

foo() // works

function foo() {
	// ...
}

foo() // works

Because of function hoisting, the function declared this way can be called both after and before declaration.

The association between the identifier foo and function value happens during compile phase of the code

Function Expression

1. Named Function Expression

   var foo = function bar() {
   	// ...
   }
   

2. Anonymous Function Expression

   var foo = function(){
   	// ...
   }	
   

foo() can be called only after creation

• the above function is not associated with it’s identifier foo until that statement during runtime

My recommendation: Use Function Expression, because it makes it clear that foo is a variable containing a function value

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tags: javascript

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