在打字稿中定义对象键的类型

Question

我是打字稿的新手，我想为我的对象键定义类型，我已经检查了几种方法来实现它，但是在分配不同类型的值时不会抛出错误。例如

interface sectionProp { 
    _type1: String,
    _columnStrechAllowed: Boolean,
    _columnOccupancy: Number,
    is_mandatory: Boolean
}


export class sectionProperties {
  folioSectionContentProp = <sectionProp> {}

  constructor(type?) {
    this.folioSectionContentProp._type1 = type;
    this.folioSectionContentProp._columnStrechAllowed = false;
    this.folioSectionContentProp._columnOccupancy = 6;
    this.folioSectionContentProp.is_mandatory = false;
  }

}

export class createNewSection extends sectionProperties {
  constructor() {
    super("Test") // here I will assign value
 // super(12)     //@ this does not generate any error as well
 // I might assign value by some other way (from object creation) 
 // but I want to know the reason if type is defined then it should 
 // not accept any value other than type 
  }

}

var z = new createNewSection();
console.log(z)

PS：我想定义我的对象键类型

谢谢

Answer 1

问题是你实际上并没有在sectionProperties 的构造函数中为type 参数指定一个值，所以它被假定为any，并且任何东西都可以被分配给任何东西。你需要一个明确的类型注解：

interface sectionProp {
    _type1: String,
    _columnStrechAllowed: Boolean,
    _columnOccupancy: Number,
    is_mandatory: Boolean
}


export class sectionProperties {
    folioSectionContentProp = <sectionProp>{}

    constructor(type: string) {
        this.folioSectionContentProp._type1 = type;
        this.folioSectionContentProp._columnStrechAllowed = false;
        this.folioSectionContentProp._columnOccupancy = 6;
        this.folioSectionContentProp.is_mandatory = false;
    }

}

export class createNewSection extends sectionProperties {
    constructor() {
        super("Test") // here I will assign value
        // super(12)     //would be an error
    }

}

您可以考虑指定 noImplicitAny 编译器选项来强制您指定编译器无法推断的类型。