Nicky_Cookie

Family of Nicky and Cookie

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class

'use strict'
class Task{

}
console.log(typeof Task);//function

'use strict'
class Task{

}
let task = new Task();
console.log(typeof task);//object
console.log(task instanceof Task);//true

same as add function to prototype

'use strict'
class Task{
	showId(){
		console.log('99');
	}
}
let task = new Task();
console.log(task.showId===Task.prototype.showId);//true

constructor

'use strict'
class Task{
	constructor(){
		console.log('constructing Task');
	}//没有逗号
	showId(){
		console.log('99');
	}
}
let task = new Task();//'constructing Task'

syntax error

'use strict'
class Task{
	let taskId=9000;
	constructor(){
		console.log('constructing Task');
	}//没有逗号
	showId(){
		console.log('99');
	}
}
let task = new Task();//'constructing Task'

difference between es5 and es6

let Task = function(){
	console.log('constructing Task');
};
let task = {};
Task.call(task);
//------------------------------------------
class Task{
	constructor(){
		console.log('constructing Task');
	}
};
let task = {};
Task.call(task);//syntax error

difference between es5 and es6

function Project(){}
console.log(window.Project === Project);//true
//------------------------------------------------
class Task{}
console.log(window.Task === Task);//false,namespace不同

extends

class Project{
	constructor(){
		console.log('constructing Project');
	}
}

class SoftwareProject extends Project{
}

let p = new SoftwareProject();//'constructing Project'

class Project{
	constructor(name){
		console.log('constructing Project '+ name);
	}
}

class SoftwareProject extends Project{
}

let p = new SoftwareProject('Mazatlan');//'constructing Project Mazatlan'

super

class Project{
	constructor(){
		console.log('constructing Project');
	}
}

class SoftwareProject extends Project{
	super();
	console.log('constructing Software');
}

let p = new SoftwareProject('Mazatlan');
//'constructing Project'
//'constructing Software'

class Project{
	getTaskCount(){
		return 50;
	}
}

class SoftwareProject extends Project{
	getTaskCount(){
		return 66;
		//also can return super.getTaskCount()+5;
	}
}

let p = new SoftwareProject('Mazatlan');
p.getTaskCount();//66

same as class

let project = {
	getTaskCount(){return 50;}
};
let softwareProject = {
	getTaskCount(){
		return super.getTaskCount()+7;
	}
};

Object.setPrototypeOf(softwareProject,project);
console.log(softwareProject.getTaskCount());//57

properties for class, es6之前都是用this关键字

class Project{
	constructor(){this.location='Mazation'}
}

class SoftwareProject extends Project{
	constructor(){
		super();
		this.location = this.location + 'Beach'
	}
}

let p = new SoftwareProject();
console.log(p.location);//'Mazation Beach'

static Members

class Project{
	static getDefaultId(){
		return 0;
	}
}
console.log(Project.getDefaultId());//0

class Project{
	static getDefaultId(){
		return 0;
	}
}
let p = new Project()
console.log(p.getDefaultId());//syntax error

class Project{
	static let id=0;
}
console.log(Project.id);//syntax error

class Project{
}
Project.id = 99;
console.log(Project.id);//99

new.target

class Project{
	constructor(){
		console.log(typeof new.target);
		console.log(new.target);
	}
}
var p= new Project();