Question

假设我将使用TypeA：一些参数，而TypeB：类本身的类型来构造函数类的构造函数，我可以使用

functionName(argument: TypeA): TypeB {
    this.property = argument;
    return this;
  }

但不能使用

property: (argument: TypeA): TypeB => ({
    property: argument,
    ...
  })

我了解这是由于使用箭头功能和普通功能时this的不同。

然后，我该如何使用箭头功能，使其与第一种正常功能的情况一样工作？

示例：

import personConst from './personConst';
// const personConst: { [key: string]: UnitBase } = {
//   brah: {
//     name: "Thomas",
//     age: 25,
//     gender: "male"
//   },
//   hoge: {
//     name: "Sarah",
//     age: 29,
//     gender: "female"
//   },
//   ...
// }

import { PersonBase } from './PersonBase';
// export interface UnitBase {
//   name: string;
//   age: number;
//   gender: string;
// }


interface Person extends PersonBase {
  income: number;
  zip: number;
  setIncome(newIncome: number): this;
  setZip(newZip: number): this;
}

const person = (key: string): Person => ({
  income: 50000,
  zip: 50000,
  setIncome: (newHp: number): Person => ({
    income: newIncome,
    ... // Error: Expression expected.
  }),
  setZip(newZip: number): Person {
    this.zip = newZip;
    return this; // OK
  },
  ...personConst[key]
});

export default person;

Answer 1

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(function(x){ return y })

我认为表现为您想要的：

const person = (key: string): Person => ({
  income: 50000,
  zip: 50000,
  setIncome: function(newIncome: number): Person { // anonymous function
    return {
      ...this, 
      income: newIncome
    };
  },
  setZip(newZip: number): Person {
    this.zip = newZip;
    return this; // OK
  },
  ...personConst[key]
});

但是我不能从你的问题中分辨出来。无论如何，希望能有所帮助；祝你好运！

Link to code

Answer 2

您不能在任何地方使用粗箭头。它最常用的： -使用粗箭头（=>），无需使用“功能”关键字。其匿名功能 -为了避免在构造函数中进行绑定，可以使用（=>） -对于doSomething（）{}之类的函数，您不能在此处使用粗箭头。但是，例如：function（）{}，您可以在此处使用lambda。

如何在JS / TS函数编程中将箭头函数用作属性

2 个答案: