[英]Jest test Fat Arrow in class missing this
I'm writing unit tests for a Component in Jest and I'm currently just testing functionality. 我正在Jest中为组件编写单元测试,而我目前仅在测试功能。
The class function is as followed: 类函数如下:
class Comp extends Component {
fetch = null;
update = async () => {
try {
if(this.fetch)
this.fetch.cancel();
// Do stuff
this.fetch = createFetch();
await this.fetch();
} catch (e) {
console.log('Error in update!!!', e);
}
}
render() {
return(
<div></div>
)
}
}
The jest test looks like this: 开玩笑的测试看起来像这样:
test('Should call fetch.cancel if fetch exists', async () => {
const spy = jest.fn();
const comp = new Comp();
comp.fetch = {cancel: spy};
await comp.update();
expect(spy).toHaveBeenCalledTimes(1);
});
But I'm getting this error from the update function: 但是我从更新功能得到这个错误:
Error in update!!!
更新错误!!! ReferenceError: _this3 is not defined
ReferenceError:_this3未定义
Can anyone help me with this? 谁能帮我这个?
I assume the problem is not the arrow function in Jest, but the class property in your Comp class. 我认为问题不是Jest中的arrow功能,而是您的Comp类中的class属性。 Take a look at this: http://babeljs.io/docs/plugins/transform-class-properties
看一下这个: http : //babeljs.io/docs/plugins/transform-class-properties
Edit: It worked after setting the spec mode: http://2ality.com/2017/01/babel-esm-spec-mode.html 编辑:在设置规范模式后可以使用: http : //2ality.com/2017/01/babel-esm-spec-mode.html
Modules transpiled in this mode conform as closely to the spec as is possible without using ES6 proxies
在不使用ES6代理的情况下,以这种模式转译的模块尽可能符合规格要求
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