anonymous functions javascript code example

Example 1: js anonymous function es6

// (param1, param2, paramN) => expression

// ES5
var multiplyES5 = function(x, y) {
  return x * y;
};

// ES6
const multiplyES6 = (x, y) => { return x * y };

Example 2: anonymous function javascript

// There are several definitions

// Non-anonymous, you name it
function hello() { /* code */ }
// Call as usual
hello()

// The myriad of anonymous functions

// This is actually anonymous
// It is simply stored in a variable
var hello = function() { /* code */ }
// It is called the same way
hello()

// You will usually find them as callbacks
setTimeout(function(){ /* code */ }, 1000)
// jQuery
$('.some-element').each(function(index){ /* code */ })

// Or a self firing-closue
(function(){ /* code */ })()

Example 3: js anonymous functions

// ES5
var multiplyES5 = function(x, y) {
  return x * y;
};

// ES6
const multiplyES6 = (x, y) => { return x * y };

Example 4: anonymous function javascript

//Anonymous function; It's not assigned to an indentifier

Array.forEach((arguments) => {
	//This is an anonymous function
})

function forEach(arguments) {
	//This is NOT an anonymous function
}

Example 5: anonymous functions javascript

// Regular function, called explicitly by name .aka “named function”
function multiply(a, b){
	var result = a * b; 
	console.log(result);
} 
multiply(5, 3);

// Anonymous function stored in variable. 
// Invoked by calling the variable as a function
// Anonymous functions don't have a name, 
// so the parentheses appears right after “function” keyword.
var divided = function() {
	var result = 15 / 3;
	console.log("15 divided by 4 is "  + result);
}
divided();

// Immediately Invoked Function Expression.
// Immediately invoked function expressions are anonymous functions 
// with another parentheses pair at the end to trigger them, 
// all wrapped inside parentheses.
// Runs as soon as the browser finds it: 
(function() {
	var result = 20 / 10;
	console.log("20 divided by 10 is " + result);
}())