javascript - 使用 unstated.js 进行解构

Question

我有这个 Unstated 容器:

import { Container } from 'unstated';
import axios from 'axios';

export default class CurrenciesContainer extends Container {
  state = { currencies: null };
  async fetch() {
    const { data: currencies } = await axios.get('http://localhost:8080/get-currencies');
    this.setState({ currencies });
  }
}

以及利用它的函数:

static renderCurrencies() {
  return (
    <Subscribe to={[CurrenciesContainer]}>
      {(currencies) => {
        if (!currencies.state.currencies) {
          currencies.fetch();
        }
        return <small>Currencies: {currencies.state.currencies}</small>;
      }}
    </Subscribe>
  );
}

我想尝试解构进入 <Subscribe> 的参数像这样:

static renderCurrencies() {
  return (
    <Subscribe to={[CurrenciesContainer]}>
      {({ state, fetch }) => {
        if (!state.currencies) {
          fetch();
        }
        return <small>Currencies: {state.currencies}</small>;
      }}
    </Subscribe>
  );
}

但这打破了 Uncaught (in promise) TypeError: this.setState is not a function

显然它没有正确绑定(bind)，但我不确定为什么函数的解构会改变它的绑定(bind)。任何人都能够提供这样的解释/方式吗？谢谢!

Answer 1

将 async fetch() {} 替换为 fetch = async () => {} 以实现正确的绑定(bind)。

在你的 Unstated 容器中试试这个:

import { Container } from 'unstated';
import axios from 'axios';

export default class CurrenciesContainer extends Container {
  state = { currencies: null };
  fetch = async () => {
    const { data: currencies } = await axios.get('http://localhost:8080/get-currencies');
    this.setState({ currencies });
 }
}