Question

为什么flowtype会报告以下错误，以及如何将其记录为按预期工作？

index.js:7
  4: console.log(MY_OBJECT.getName());
                           ^^^^^^^ property `getName`. Property not found in
  4: console.log(MY_OBJECT.getName());
                 ^^^^^^^^^ new object

index.js

// @flow
import {MyObject} from './object';
const MY_OBJECT = new MyObject('name');
console.log(MY_OBJECT.getName());

object.js：

// @flow
export function MyObject(name: string) {
    this._name = name;
    this.getName = function (): string {return this._name;};
    this.setName = function (name: string) {this._name = name;};
}

Answer 1

Flow并不喜欢这种风格。当你在同一个模块中使用它时，它会起作用，但是当你从另一个文件中导入它时，它就不会。

建议改为使用ES2015 class syntax：

// @flow
export class MyObject {
    name: string;

    constructor(name: string){
        this.name = name;
    }

    getName() {
        return this.name;
    }

    setName(name: string) {
        this.name = name;
    }
}

如果您不喜欢这样，可以使用原型has limited support：

// @flow
export function MyObject(name: string) {
  this._name = name;        
}

MyObject.prototype.getName = function (): string {return this._name;};
MyObject.prototype.setName = function (name: string) {this._name = name;};

Answer 2

我只是想通了，当它明确地返回时它确实有效：

// @flow
export function MyObject(name: string) {
    this._name = name;
    this.getName = function (): string {return this._name;};
    this.setName = function (name: string) {this._name = name;};
    return this;
}

简单构造函数中的Flowtype错误

2 个答案: