Module System

Function Declarations and Expressions

The function name can be omitted in function expressions
This creates an anonymous function
Typically, a function expression is used as an IIFE
As a result, function expressions run as soon as its defined
Consequently, they aren't hoisted to the global scope

Illustrating Declarations and Expressions

// function declaration
function multiply(num1, num2) {
    return num1 * num2;
}

// function expression
let multiply = function(num1, num2) {
    return num1 * num2;
}

Illustrating Function Hoisting

hoisted(); // logs "foo"
notHoisted(); // TypeError: notHoisted not a function

function hoisted() {
    console.log('foo');
}

var notHoisted = function() {
    console.log('bar');
};

Sample Structure of Modules

Refer to this project for more information

index.html
main.js
modules/
    canvas.js  // module
    square.js  // module

References

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Currying

Event Loop