SOLVED - var functionName = function() {} vs function functionName() {}

 

var functionName = function() {} vs function functionName() {}

 

Function declaration vs Function expression

A function declaration is a declaration; it's not a statement or expression.

A function declaration is processed when execution enters the context in which it appears, before any step-by-step code is executed. The function it creates is given a proper name , and that name is put in the scope in which the declaration appears.

functionOne - It is a function expression and so only defined when that line is reached.

functionTwo- It is a function declaration and is defined as soon as its surrounding function or script is executed.
 

Example- 

Function Expression


// TypeError: functionOne is not a function
functionOne();

var functionOne = function() {
  console.log("Hello!");
};

 Function declaration:

// Outputs: "Hello!"
functionTwo();

function functionTwo() {
  console.log("Hello!");
}