flowtype - 无法将对象文字分配给 `...`，因为对象文字 [1] 中缺少属性 `...` 但存在于 `...`

Question

我是新流程，目前正在处理流程严格的项目。我有一个类型别名被传递给一个类。可以找到该片段here

// @flow strict

export type CustomType = {
  a: string,
  b: boolean,
  c: boolean,
  d: boolean,
  e: boolean
};
let d = true;
let b = true;
let customType:CustomType = {
        d,
        b,
        c: true,
 }

class Custom{
  constructor(customType = {}) {}
}

let custom = new Custom(customType);

传递对象时，并非所有属性 customType 都存在。这里最好的解决方法是什么？

Answer 1

您可以键入 CustomType 的键对象为 optional :

( Try )

// @flow strict

export type CustomType = {
  a?: string,
  b?: boolean,
  c?: boolean,
  d?: boolean,
  e?: boolean
};
let d = true;
let b = true;
let customType: CustomType = {
        d,
        b,
        c: true,
 }

class Custom{
  constructor(customType: CustomType = {}) {}
}

let custom = new Custom(customType);

或者，您可以使用 $Shape<T> .它只允许您传递您感兴趣的 key :

( Try )

// @flow strict

export type CustomType = {
  a: string,
  b: boolean,
  c: boolean,
  d: boolean,
  e: boolean
};
let d = true;
let b = true;
let customType: $Shape<CustomType> = {
        d,
        b,
        c: true,
 }

class Custom{
  constructor(customType: $Shape<CustomType> = {}) {}
}

let custom = new Custom(customType);