javascript - 无法让 Redux 在生成器函数中运行

Question

编辑 1

所以我现在已经按照建议更新了 projectorSaga 函数以使用 yield call()，但我现在每次调用该函数时都会收到以下错误，我认为这是由于我嵌套函数和返回 promise 的方式所致不是返回 promise 的函数，但我对如何重组它来修复它有点不知所措。

redux-saga error: uncaught at check
call: argument [object Promise] is not a function
[14:57:43.351] [verbose] Error: call: argument [object Promise] is not a function

这里是update saga的代码，其他功能依旧如下。

import { put, takeEvery, call } from 'redux-saga/effects';

import * as pjControl from '../../pjcontrol/pjControl';

import { TURNON, TURNOFF, SENDCOMMAND, SHUTTERCLOSE, SHUTTEROPEN } from '../actions/actionTypes';

const log = require('electron-log');

const ip = '192.168.100.100';
const port = 3629;
const model = 'L1500';

function* sendCommand(payload) {
  yield put({ type: 'SENDING COMMAND', payload });
  try {
    let response;
    const command = payload.payload.command;
    if (command === TURNON) {
      response = yield call(pjControl.turnOn(ip, port, model));
    } else if (command === TURNOFF) {
      response = yield call(pjControl.turnOff(ip, port, model));
    } else if (command === SHUTTERCLOSE) {
      response = yield call(pjControl.shutterClose(ip, port, model));
    } else if (command === SHUTTEROPEN) {
      response = yield call(pjControl.shutterOpen(ip, port, model));
    } else {
      throw Error('Unknwon Command');
    }
    log.verbose(response);
    yield put({ type: 'SEND_COMMAND_SUCCEEDED', response });
  } catch (e) {
    log.verbose(e);
    yield put({ type: 'SEND_COMMAND_FAILED', e });
  }
}

export default function* projectorSetSaga() {
  yield takeEvery(SENDCOMMAND, sendCommand);
}

原创

我刚刚开始尝试在我一直在使用的 Electron 应用程序中使用 Redux-Saga，但我在使用我的生成器函数之一时遇到了问题。我怀疑是我不理解 say 函数和回调等的嵌套，但到目前为止，我已经以多种方式尝试过这一点，但没有任何区别。

问题的奇怪之处在于 sendCommand 中的初始 yield 确实导致事件出现在 Redux 中。此外，我的日志命令确实会在我期望的时候以正确的值被调用。如果连接超时，将调用 catch 中的日志，但 throw 命令都不会出现在 Redux 中。

这是我的根传奇:

import { all, call } from 'redux-saga/effects';

import projectorGetSaga from './projectorGetSaga';
import projectorSetSaga from './projectorSetSaga';

export default function* rootSaga() {
  yield all([
    call(projectorGetSaga),
    call(projectorSetSaga),
  ]);
}

这是我正在努力解决的 projectorSetSaga。

import { put, takeEvery } from 'redux-saga/effects';

import * as pjControl from '../../pjcontrol/pjControl';

import { TURNON, TURNOFF, SENDCOMMAND, SHUTTERCLOSE, SHUTTEROPEN } from '../actions/actionTypes';

const log = require('electron-log');

const ip = '192.168.100.100';
const port = 3629;
const model = 'L1500';

function* sendCommand(payload) {
  yield put({ type: 'SENDING COMMAND', payload });
  try {
    let response;
    const command = payload.payload.command;
    if (command === TURNON) {
      response = yield pjControl.turnOn(ip, port, model);
    } else if (command === TURNOFF) {
      response = yield pjControl.turnOff(ip, port, model);
    } else if (command === SHUTTERCLOSE) {
      response = yield pjControl.shutterClose(ip, port, model);
    } else if (command === SHUTTEROPEN) {
      response = yield pjControl.shutterOpen(ip, port, model);
    } else {
      throw Error('Unknwon Command');
    }
    log.verbose(response);
    yield put({ type: 'SEND_COMMAND_SUCCEEDED', response });
  } catch (e) {
    log.verbose(e);
    yield put({ type: 'SEND_COMMAND_FAILED', e });
  }
}

export default function* projectorSetSaga() {
  yield takeEvery(SENDCOMMAND, sendCommand);
}

这是 saga 正在调用的函数的其余代码，因为它可能是相关的，我可能完全误解了需要返回异步函数/promises 等的方式。

sendCommand函数调用的PJ Control函数如下。

import * as epsonControl from './epson/epsonControl';
import { manufacturerlLookup, commandLookup } from './pjLookups';

function sendCommand(ip, port, model, command, input) {
  const manufacturer = manufacturerlLookup(model);
  const mappedCommand = commandLookup(manufacturer, command, input);
  switch (manufacturer) {
    case 'epson':
      return epsonControl.sendCommand(ip, port, mappedCommand);
    default:
      return null;
  }
}




exports.turnOn = (ip, port, model) => sendCommand(ip, port, model, 'PWR ON');

exports.turnOff = (ip, port, model) => sendCommand(ip, port, model, 'PWR OFF');

exports.shutterOpen = (ip, port, model) => sendCommand(ip, port, model, 'MUTE OFF');

exports.shutterClose = (ip, port, model) => sendCommand(ip, port, model, 'MUTE ON');

exports.setInput = (ip, port, model, input) => sendCommand(ip, port, model, 'SOURCE', input);

exports.getPowerStatus = (ip, port, model) => sendCommand(ip, port, model, 'PWR?');

exports.getShutterStatus = (ip, port, model) => sendCommand(ip, port, model, 'MUTE?');

exports.getInputStatus = (ip, port, model) => sendCommand(ip, port, model, 'SOURCE?');

最后，实际的异步函数，实际上是通过 return/throw 返回一个 promise。

exports.sendCommand = async (host, port, command) => {
  log.info(`sending command ${command} to ${host}`);

  // throw new Error('Oh dear!');
  // Set a time to cancel the operation if the connection times out
  const mergedCommand = `${command}\r`;
  // Create a new client
  const socket = new net.Socket();

  socket.setTimeout(1000);

  const client = new PromiseSocket(socket);

  await client.connect({ host, port });

  await client.write(buildBuffer(handshake));

  client.stream.on('data', (data) => {
    if (data.toString() === response) {
      log.verbose(`Got handshake, sending command ${command}`);
      client.write(buildBuffer(mergedCommand));
    } else if (data.toString() === ':') {
      // log.verbose('command executed successfully, disconnecting');
      sendStatus(data.toString(), host);
      client.end();
      return (true, 'command');
    } else {
      const respose = data.toString().substring(0, data.toString().length - 2);
      // log.verbose(`got status ${response} disconnecting`);
      sendStatus(respose, host);
      client.end();
      return (true, 'command', data);
    }
  });
};

Answer 1

我认为您正在yielding(暂停)生成器函数而不调用 next。 Saga 有这方面的功能。例如，不是在函数调用时产生，而是在 saga 函数 call 上产生。

所以应该是:

 try {
    let response;
    const command = payload.payload.command;
    if (command === TURNON) {
      response = yield call([pjControl,'turnOn'],ip, port, model);
    } 
 ... 

请参阅https://redux-saga.js.org/docs/api/