interface Vegetables { color: string; } interface Tomato extends Vegetables { radius: number; } interface Carrot extends Vegetables { length: number; } const tomato: Tomato={ radius:1.2//error Property 'color' is missing in type '{ radius: number; }'}; const carrot: Carrot={ color:"orange...
typeof null; 结果为"object" typeof document.all; 在IE外的其他现代浏览器下会返回"undefined",但实际上是可用的(该方法被大量用作判断IE,因此浏览器厂商也有对应规则)。 typeof document.childNodes; 在safari下结果为"function" typeof document.createElement('embed'); 在firefox下结果为"function" typeof d...
interfacePoint{x:number;}interfacePoint{y:number;}constpoint:Point={x:1};//error Property 'y' ...
interface Point { y: number; }//等价于interface Point { x: number; y: number; } ⏰type 6. only interface can 🔊:在实际开发中,有的时候也会遇到interface能够表达,但是type做不到的情况:「给函数挂载属性」 interface FuncWithAttachment { (param: string):boolean; someProperty: number; } cons...
interface Person { name: string; gender: boolean; age?...interface Person { name: string; gender: boolean; age?...interface Person { name: string;...
interfaceA{good(x:number):string,bad(x:number):string}interfaceBextendsA{good(x:string|number):string,bad(x:number):number// Interface 'B' incorrectly extends interface 'A'.// Types of property 'bad' are incompatible.// Type '(x: number) => number' is not assignable to type '(x: ...
这里我就有点困惑了,因为以前写别的强类型面向对象语言,interface一般都是用来描述高度抽象的行为所以一般情况下只定义方法(即使在语法上可以在interface中定义property,一般也不会这么去做),而property一般都是定义在class这个层面的。 由于没有系统学习过ts(基本就靠以前其它的语言经验拿来就上手了),所以这里请大家给...
Cannot assign to 'x' because it is a constant or a read-only property. 额外的属性检查 为了能够允许 interface 接受没有存在的属性,可以这样写: 推荐: 字符串索引签名 [propName:string]:any interface SquareConfig { color?: string; width?: string; [propName:string]: any; } const square:Square...
interface Obj{[keyin'id'|'name']:any;//TS1169:A computed property nameinan interface must refer to an expression whose typeisa literal typeora'unique symbol'type.}; 1. 2. 3. 因为interface 类型的属性必须是字面量类型(string、number) 或者是 unique symbol 类型,所以 在第 2 行提示了 TS116...
interface Person { name: string; age?: number; [propName: string]: string; } let tom: Person = { name: 'Tom', age: 25, gender: 'male' }; // index.ts(3,5): error TS2411: Property 'age' of type 'number' is not assignable to string index type 'string'. ...