Typescript from getting started to mastering (19) enumeration types

Write a little demo
Random number drinking game , We shake a few at random and drink a few drinks

Write a random number Random generation 0-6

const RandomNumber = Math.round(Math.random()*6)

Write another way

function Drink(num:number):string{
    
    if(num==0){
    
        return " No drinking "
    }else if(num==1){
    
        return " Have a drink "
    }else if(num==2){
    
        return " Have two drinks "
    }else if(num==3){
    
        return " Drink three cups "
    }else if(num==4){
    
        return " Drink four cups "
    }else if(num==5){
    
        return " Drink five cups "
    }else if(num==6){
    
        return " Drink six cups "
    }
    
}
console.log(Drink(RandomNumber))

This simply completes our requirements , But the above writing is the writing of beginners .
Let's transform , The following code

const RandomNumber = Math.round(Math.random()*6)

const Status ={
    
   zero:0,
   one:1,
   two:2,
   three:3,
   four:4,
   five:5,
   six:6,
}

function Drink(num:number):string{
    
    if(num==Status.zero){
    
        return " No drinking "
    }else if(num==Status.one){
    
        return " Have a drink "
    }else if(num==Status.two){
    
        return " Have two drinks "
    }else if(num==Status.three){
    
        return " Drink three cups "
    }else if(num==Status.four){
    
        return " Drink four cups "
    }else if(num==Status.five){
    
        return " Drink five cups "
    }else if(num==Status.six){
    
        return " Drink six cups "
    } 
}
console.log(Drink(RandomNumber))

But the top is not high enough , Advanced writing will use our enumeration types enum, The following code

const RandomNumber = Math.round(Math.random()*6)
enum Status {
    
    zero,
    one,
    two,
    three,
    four,
    five,
    six
}
function Drink(num:number):string{
    
    if(num==Status.zero){
    
        return " No drinking "
    }else if(num==Status.one){
    
        return " Have a drink "
    }else if(num==Status.two){
    
        return " Have two drinks "
    }else if(num==Status.three){
    
        return " Drink three cups "
    }else if(num==Status.four){
    
        return " Drink four cups "
    }else if(num==Status.five){
    
        return " Drink five cups "
    }else if(num==Status.six){
    
        return " Drink six cups "
    } 
}
console.log(Drink(RandomNumber))

The corresponding value of enumeration type

At this point, we pass a value 1, Will be output Have a drink

console.log(Drink(1));
// Print the results : Have a drink 

It looks amazing , This is because enumeration types have corresponding numeric values , The default is 0 At the beginning . We just use console.log() You can see that .

console.log(Status.zero); // The result is ：0
console.log(Status.one);// The result is ：1
console.log(Status.two);// The result is ：2
console.log(Status.three);// The result is ：3
console.log(Status.four);// The result is ：4
console.log(Status.five);// The result is ：5
console.log(Status.six);// The result is ：6

To see the result is 0,1,2,3,4,5,6. At this time, I don't want to default from 0 Start , I want to start with 10 Start . It can be written like this

enum Status {
    
    zero = 10,
    one,
    two,
    three,
    four,
    five,
    six
}

We can Enumeration is inverted by subscript Check whether it is from 10 At the beginning

console.log(Status.zero)
console.log(Status.one)
console.log(Status[10])
console.log(Status[11])

The output result is ： 1011zeroone