// 通过接口(interface) 声明对象类型interfaceInfoType{readonlyname:string// 只读属性age?:number// 可选属性height:number}// 指定对象的类型constinfo:InfoType= {name:'zhangsan',age:20,height:170}console.log(info.name);// info.name = 'lisi'; // 只读属性不能修改info.age=22;// 可以修改 如上...
}typeStringOrNumberFunc=(ns:string|number) =>void;letfunc:StringOrNumberFunc= fn;// 不能将类型“(x: string) => void”分配给类型“StringOrNumberFunc”。// 参数“x”和“ns” 的类型不兼容。// 不能将类型“string | number”分配给类型“string”。// 不能将类型“string | number”分配给类...
Type '{ 42?: string | undefined; }' is not assignable to type '{ [key: number]: string; }'. sortOfArrayish = numberKeys; You can get a better sense of this change by reading up on the original PR. Declare Missing Helper Function Thanks to a community pull request from Alexander ...
this.fullname = firstname + " " + lastname; } greet(name?: string) { if (name) { return "Hi! " + name + "! my name is " + this.fullname; } else { return "Hi! my name is " + this.fullname; } } } var spark = new Character("Jacob", "Keyes"); var msg = spark.g...
Head]&number>,Tail]:[Identifier<Head&string>,Tail]:[Identifier<T&string>,''];typeParseMember...
export function tokenToString(t: SyntaxKind): string | undefined { return tokenStrings[t]; } /* @internal */ export function stringToToken(s: string): SyntaxKind | undefined { return textToToken.get(s); } 1. 2. 3. 4. 5.
/** * Convert first character of string literal type to uppercase */ type Capitalize<S extends string> = intrinsic; 用法 type DogName = "linlin" type CapitalizeDogName = Capitalize<DogName> // 得到 "LinLin" Uncapitalize 将字符串的字面量类型首字母转换为小写 Uncapitalize 的实现为编译器内置...
{command:`_typescript.goToSourceDefinition`arguments:[lsp.DocumentUri,// String URI of the documentlsp.Position,// Line and character position (zero-based)]} Response: lsp.Location[]|null (This command is supported from Typescript 4.7.) ...
function greet(person: { name: string; age: number }) { return "Hello " + person.name; } You can also use the interface to define: interface Person { name: string; age: number; } function greet(person: Person) { return "Hello " + person.name; ...
The new primitive type bigint can be accessed by calling the BigInt() function or by writing out a BigInt literal by adding an nto the end of any integer numeric literal. Also, bigints produce a new string type when using the typeof operator: the string bigint. BigInt support is ...