JS记录

1. create JS object

(1)

var myCar = new Object();
myCar.make = 'Ford';
myCar.model = 'Mustang';
myCar.year = 1969;

console.log(myCar.make)
// terminal 执行 node ex2.js

(2)

var myCar = {
    'make' : 'Ford', 
    'model' : 'Mustang',
    'year' : 1969
}

(3) constructors 

function Car(make, model, year){
    this.make = make;
    this.model = model;
    this.year = year;
}
var myCar = new Car('Ford', 'Mustang', 1969)

(4) class

class Car{
    constructor(make, model, year){
        this.make = make;
        this.model = model;
        this.year = year;
    }
}
var myCar = new Car('Ford', 'Mustang', 1969);

2. access properties

(1)  mycar.make 

(2)  mycar['make'] 

3. class methods

class Car{
    constructor(make, model, year){
        this.make = make;
        this.model = model;
        this.year = year;
    }
    printCarDetails(){
        console.log(`***${this.make}***`)
    }  
}

4. compare objects

==：casts are performed on both sides

===：no casts

5. functions

function add(firstNum,secondNum){
    return firstNum + secondNum
}

var addNum = function(firstNum,secNum){
    return firstNum + secNum;
}

arrow funtion expression, cannot be used as construntors

const addNumArror = (firstNum,secNum)=>{
    return firstNum + secNum;
}

 6. 杂七杂八

for( p in pList) => p是index
for (var p of pList ) => p是each item