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我对 react 很陌生，考虑到不同代码风格在 react 中的流行，我发现将我的第一个应用程序放在一起有点令人困惑。

该应用程序的目的是使用基于表单输入的动态查询来执行 GraphQL 查询。在第一次渲染时，它应该使用状态中提供的数据。当用户更改标准值时，应执行新的 GrapQl。但是，在尝试更改输入值时，只要我按下按钮并且在（！）更新值之前，就会释放一个新请求。

我尝试了不同的方法，但都没有产生任何变化。

这是我的代码和应用程​​序

由于我的 GraphQL 服务器在本地运行，您应该期望得到以下回报：

{
"data": {
    "sensorDataTimeSeriesCurve": [
    {
        "timestamp": "2019-06-12T04:00:00",
        "value": 31.01
    },
    {
        "timestamp": "2019-06-12T05:00:00",
        "value": 33.08
    },
    {
        "timestamp": "2019-06-12T06:00:00",
        "value": 34.28
    }
    ]
}
}

src/index.js

import React, { Component } from "react";
import { render } from "react-dom";

import ApolloClient from "apollo-boost";
import { ApolloProvider, useQuery } from "@apollo/react-hooks";
import gql from "graphql-tag";
import Chart from "./components/charts/chart";

const client = new ApolloClient({
  uri: `https://GRAPHQLENDPOINT`
});

const timeseriesQuery = gql`
  query test0($id1: ID!, $from: DateTime!, $to: DateTime!) {
    sensorDataTimeSeriesCurve(id: $id1, from: $from, to: $to) {
      timestamp
      value
    }
  }
`;

function Timeseries({ id1, from, to }) {
  const { loading, error, data, refetch, networkStatus } = useQuery(
    timeseriesQuery,
    {
      variables: { id1, from, to },
      notifyOnNetworkStatusChange: true
      // pollInterval: 500
    }
  );

  if (networkStatus === 4) return "Refetching!";
  if (loading) return null;
  if (error) return `Error!: ${error}`;
  console.log("Data:", data);

  return (
    <div>
      <Chart data={data.sensorDataTimeSeriesCurve} />
      <button onClick={() => refetch()}>Refetch!</button>
    </div>
  );
}

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      id1: 20742,
      from: "2019-06-12 03:56:13.567",
      to: "2019-06-22 04:56:13.567"
    };
  }
  handleChange = event => {
    let name = event.target.name;
    let value = event.target.value;
    this.setState({ [name]: value });
  };

  render() {
    return (
      <ApolloProvider client={client}>
        <div>
          <form onSubmit={this.handleSubmit}>
            <label>
              Name:
              <input
                type="text"
                value={this.state.id1}
                onChange={this.handleChange}
              />
            </label>
            <label>
              From:
              <input
                type="text"
                value={this.state.from}
                onChange={this.handleChange}
              />
            </label>
            <label>
              To:
              <input
                type="text"
                value={this.state.to}
                onChange={this.handleChange}
              />
            </label>
            <input type="submit" value="Submit" />
          </form>
          {this.state.id1 && (
            <Timeseries
              id1={this.state.id1}
              from={this.state.from}
              to={this.state.to}
            />
          )}
        </div>
      </ApolloProvider>
    );
  }
}

render(<App />, document.getElementById("root"));

src/components/charts/charts.js

import { LineChart, Line } from "recharts";
import React from "react";

class Chart extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      data: this.props.data
    };
  }

  render() {
    return (
      <LineChart width={400} height={400} data={this.state.data}>
        <Line type="monotone" dataKey="value" stroke="#8884d8" />
      </LineChart>
    );
  }
}

export default Chart;

My expected behavior is that a new GraphQL request is made after pressing the submit button.

The actual behavior is that right now, as soon as I attemp to change the input fields, a new request is made with the existing input. It is not possible to change the input values.

4

1 回答 1

1

You query is being sent whenever you render the Timeseries component, and the Timeseries component is being rendered right away (the initial value of you App component is truthy).
Another thing is that you don't seem to give your inputs actual names, so how should they know which value to update?

于 2019-08-23T10:13:24.517 回答