type Player = {readonly name:string, age?: number}
const nico:Player = {
name: 'nico',
}
const lynn:Player = {
name: 'lynn',
age: 22
}
if(nico.age && nico.age < 10){
}
function playerMaker(name:string):Player{
return {
name
}
}
const nico1 = playerMaker('nico')
const numbers: readonly number[] = [1, 2, 3, 4]
const player: readonly[string, number, boolean] = ['nico', 22, true]
let a:unknown;
if(typeof a === 'number') {
let b = a + 1;
}
if(typeof a === 'string') {
let b = a.toUpperCase();
}
function hello(){
console.log('x')
}
const b = hello();
b.toUpperCase()
function hello1():never{
throw new Error('xxx')
}
function hello2(name:string|number){
if(typeof name === 'string'){
name
}else if(typeof name === 'number'){
name
}else{
name
}
}