Training JavaScript

Foundation

Tiven Wang

JavaScript Series

JavaScript Foundation
Node.js
Create Server by Node.js (JavaScript version)
Create Server by Node.js (TypeScript version)
Angular for frontend development

Language basics

Variable

JavaScript is a loosely typed or a dynamic language.

Primitive

string
number
boolean
null
undefined
symbol (new in ECMAScript 6)

other

Object

Variable

boolean Conversions

false

The empty string ""
null
undefined
The number 0
The number NaN
The boolean false

true

The string "0"
The string "false"
The string " "
The number -1

Object

An object is a collection of related data and/or functionality (which usually consists of several variables and functions — which are called properties and methods when they are inside objects.)

Array is Object


var person = {
  name: ['Bob', 'Smith'],
  age: 32,
  gender: 'male',
  interests: ['music', 'skiing'],
  bio: function() {
    alert(this.name[0] + ' ' + this.name[1] + ' is ' + this.age + ' years old. He likes ' + this.interests[0] + ' and ' + this.interests[1] + '.');
  },
  greeting: function() {
    alert('Hi! I\'m ' + this.name[0] + '.');
  }
};

Function

points

How to define and use a function
Passing parameters to a function
Pre-defined functions that are available to you "for free"
The scope of variables in JavaScript
The concept that functions are just data, albeit a special type of data
Function has prototype that is a Object
new Function = Object
call Function

Function

points

Using anonymous functions
Callbacks
Self-invoking functions
Inner functions (functions defined inside functions)
Functions that return functions
Functions that redefine themselves
Closures

* Callbacks When you pass a function A to another function B and B executes A, it's often said that A is a callback function. If A doesn't have a name, then you can say that it's an anonymous callback function. * Self-invoking functions ```javascript ( function(name){ alert('Hello ' + name + '!'); } )('dude') ``` * Inner functions ```javascript var a = function(param) { var b = function(theinput) { return theinput * 2; }; return 'The result is ' + b(param); }; ``` 是实现OO私有方法的基础 * Functions that redefine themselves 这个例子涉及到了这几个难点。 ```javascript var a = function() { function someSetup(){ var setup = 'done'; } function actualWork() { alert('Worky-worky'); } someSetup(); return actualWork; }(); ``` * Closures In JavaScript, functions have lexical scope. This means that functions create their environment (scope) when they are defined, not when they are executed. When a function is defined, it "remembers" its environment, its scope chain。 ```javascript // code start var a = function() { return sayHello(); }(); println(a); function sayHello() { println("Hello " + this); } // code end ``` 结果是 Hello [object Object]

Scope

()
function f(){}()
(function f(){}())

Prototype

Object.prototype is a object: Object is a inner Function

Function.prototype is a function: Function is a inner Function

Closure

## TypeScript [TypeScript](https://zh.wikipedia.org/wiki/TypeScript) [CoffeeScript](http://coffeescript.org/) [ES6](http://es6-features.org) `npm install -g typescript` `tsc helloworld.ts` `node helloworld.js`

Node.js

Thank you

@tiven.wang