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/** @deprecated use User class instead */ | |
class OldUser {} | |
class User { | |
/** @deprecated */ | |
constructor(public username: string, public age: number) {} | |
/** @deprecated */ | |
static createUser(username: string, age: number) { |
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class User { | |
username: string; | |
age: number; | |
constructor(username: string,age: number) { | |
this.username = username; | |
this.age = age; | |
} | |
static [propName: string]: string | number; |
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class User { | |
username: string; | |
age: number; | |
constructor(username: string,age: number) { | |
this.username = username; | |
this.age = age; | |
} | |
[propName: string]: string | number; |
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function userCount() { | |
/* Mock data */ | |
return 15; | |
}; | |
class User { | |
id = 0; | |
static count: number = 0; | |
constructor( |
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{ | |
"compilerOptions": { | |
"noImplicitOverride": true | |
} | |
} |
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class Employee { | |
doWork() { | |
console.log('I\'m working!'); | |
} | |
} | |
class Developer extends Employee { | |
override doWork() { | |
console.log('I\'m programming!') | |
} |
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const roles = ['read', 'write', 'readAndWrite'] as const; | |
type Roles = typeof roles[number]; | |
// equals to this | |
// type Roles = "read" | "write" | "readAndWrite" | |
// or even like this | |
type RolesInCapital = Capitalize<typeof roles[number]>; | |
// equals to this | |
// type RolesInCapital = "Read" | "Write" | "ReadAndWrite" |
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const email = 'john@gmail.com'; // type 'john@gmail.com' | |
const phones = [8494922901, 1238399293]; // type number[] | |
const session = { id: 123, name: 'x1keck323jKJdf1' }; | |
// type | |
// { | |
// id: number; | |
// name: string; | |
// } | |
const username = 'John' as const; // type 'John' |
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function valueCheck(value: string | number) { | |
if (typeof value === "string") { | |
// value has type string | |
} else if (typeof value === "number") { | |
// value has type number | |
} else { | |
value; // value has type never | |
} | |
} |
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function endlessWhile(): never { | |
while(true) { | |
/* ... */ | |
} | |
} |
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