javascript - 使用 unstated.js 进行解构

Question

我有这个未说明的容器：

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 });
  }
}

而这个利用它的功能：

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<Subscribe>类似这样的参数：

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，但我不确定为什么函数的解构会改变它的绑定。任何人都能够提供这样的解释/方式吗？谢谢！

Answer 1

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

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 });
 }
}