参考讯飞的js demo iat_ws_js_demo.zip，
将代码转换成基于angular typescrirpt的语言风格
官方demo下载地址：demo下载

关键字

• 讯飞语音听写，语音识别
• typescript web worker
• html chrome 浏览器语音识别

项目文件

• home.html
• home.ts
• iat-ws.service.ts
• assets/js/transcode.worker.js

/*********************home.html**************************** */
<ion-content padding>
  <p>
    <button ion-button (click)="click()">{{btnText}} </button>
  </p>
  <p>时间：{{senconds}}</p>
  <p style="background-color: #eee; min-height: 100px;">
    {{message}}
  </p>
</ion-content>

/*********************home.ts**************************** */
import { Component, OnInit } from '@angular/core';
import { NavController  } from 'ionic-angular';
import { IatWsService } from './iat-ws.service';

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage implements OnInit {

  senconds = 0
  message = '';

  btnText = '开始识别';
  btnTextObj = {
    null: '开始识别', // 最开始状态
    init: '开始识别', // 初始化状态
    ing: '结束识别', // 正在录音状态
    end: '开始识别', // 结束状态
  }

  countInterval

  constructor(
    public navCtrl: NavController,
    private iatWsService: IatWsService,
    ) {
  }
  ngOnInit(): void {
    this.iatWsService.onWillStatusChange = (oldStatus, status) => {
      console.log(oldStatus);
      console.log(status);
      this.btnText = this.btnTextObj[status];
      if (status === 'ing') {
        // 倒计时相关
        this.countInterval = setInterval(() => {
          this.senconds++
          if (this.senconds >= 60) {
            this.iatWsService.stop()
            clearInterval(this.countInterval)
          }
        }, 1000)
      } else if (status === 'init') {
        this.senconds = 0;
      } else {
        clearInterval(this.countInterval)
      }
    }
    this.iatWsService.onTextChange = (text) => {
      console.log(text);
      this.message = text;
    }
  }

  click(): void {
    if (this.iatWsService.status === 'ing') {
      this.iatWsService.stop()
    } else {
      this.iatWsService.start()
    }
  }


}

/*********************iat-ws.service.ts**************************** */
import { Injectable } from '@angular/core';
import CryptoJS from 'crypto-js'

declare let navigator:any;
declare let window:any;


@Injectable()
export class IatWsService {

  //APPID，APISecret，APIKey在控制台-我的应用-语音听写（流式版）页面获取
  APPID = 'xxxx'
  API_SECRET = 'xxxx'
  API_KEY = 'xxx'

  status = 'null'
  language = 'zh_cn'
  accent = 'mandarin'
  appId = this.APPID
  // 记录音频数据
  audioData = []
  // 记录听写结果
  resultText = ''
  // wpgs下的听写结果需要中间状态辅助记录
  resultTextTemp = ''

  transWorker;
  onWillStatusChange: Function;
  onTextChange: any;
  webSocket: any;
  audioContext: any;
  scriptProcessor: any;
  mediaSource: any;
  handlerInterval: number;

  constructor() {
    let self = this

    this.transWorker = new Worker('/assets/js/transcode.worker.js');
    console.log(this.transWorker);

    this.transWorker.onmessage = function (event) {
      self.audioData.push(...event.data)
    }
  }

  /**
   * 获取websocket url
   * 该接口需要后端提供，这里为了方便前端处理
   */
  getWebSocketUrl() {
    return new Promise((resolve, reject) => {
      // 请求地址根据语种不同变化
      var url = 'wss://iat-api.xfyun.cn/v2/iat'
      var host = 'iat-api.xfyun.cn'
      var apiKey = this.API_KEY
      var apiSecret = this.API_SECRET
      var date = new Date().toUTCString()
      var algorithm = 'hmac-sha256'
      var headers = 'host date request-line'
      var signatureOrigin = `host: ${host}\ndate: ${date}\nGET /v2/iat HTTP/1.1`
      var signatureSha = CryptoJS.HmacSHA256(signatureOrigin, apiSecret)
      var signature = CryptoJS.enc.Base64.stringify(signatureSha)
      var authorizationOrigin = `api_key="${apiKey}", algorithm="${algorithm}", headers="${headers}", signature="${signature}"`
      var authorization = btoa(authorizationOrigin)
      url = `${url}?authorization=${authorization}&date=${date}&host=${host}`
      resolve(url)
    })
  }

  // 修改录音听写状态
  setStatus(status) {
    this.onWillStatusChange && this.status !== status && this.onWillStatusChange(this.status, status)
    this.status = status
  }
  setResultText({ resultText, resultTextTemp } = { resultText: undefined, resultTextTemp: undefined }) {
    this.onTextChange && this.onTextChange(resultTextTemp || resultText || '')
    resultText !== undefined && (this.resultText = resultText)
    resultTextTemp !== undefined && (this.resultTextTemp = resultTextTemp)
  }
  // 修改听写参数
  setParams({ language, accent } = { language: undefined, accent: undefined}) {
    language && (this.language = language)
    accent && (this.accent = accent)
  }
  // 连接websocket
  connectWebSocket() {
    return this.getWebSocketUrl().then((url:any) => {
      console.log(url);

      let iatWS
      if ('WebSocket' in window) {
        iatWS = new WebSocket(url)
      } else if ('MozWebSocket' in window) {
        alert('no MozWebSocket')
        // iatWS = new MozWebSocket(url)
      } else {
        alert('浏览器不支持WebSocket')
        return
      }
      this.webSocket = iatWS
      this.setStatus('init')
      iatWS.onopen = e => {
        this.setStatus('ing')
        // 重新开始录音
        setTimeout(() => {
          this.webSocketSend()
        }, 500)
      }
      iatWS.onmessage = e => {
        this.result(e.data)
      }
      iatWS.onerror = e => {
        this.recorderStop()
      }
      iatWS.onclose = e => {
        this.recorderStop()
      }
    })
  }
  // 初始化浏览器录音
  recorderInit() {
    navigator.getUserMedia =
      navigator.getUserMedia ||
      navigator.webkitGetUserMedia ||
      navigator.mozGetUserMedia ||
      navigator.msGetUserMedia

    // 创建音频环境
    try {
      this.audioContext = new (window.AudioContext || window.webkitAudioContext)()
      this.audioContext.resume()
      if (!this.audioContext) {
        alert('浏览器不支持webAudioApi相关接口')
        return
      }
    } catch (e) {
      if (!this.audioContext) {
        alert('浏览器不支持webAudioApi相关接口')
        return
      }
    }

    // 获取浏览器录音权限
    if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
      navigator.mediaDevices
        .getUserMedia({
          audio: true,
          video: false,
        })
        .then(stream => {
          getMediaSuccess(stream)
        })
        .catch(e => {
          getMediaFail(e)
        })
    } else if (navigator.getUserMedia) {
      navigator.getUserMedia(
        {
          audio: true,
          video: false,
        },
        stream => {
          getMediaSuccess(stream)
        },
        function (e) {
          getMediaFail(e)
        }
      )
    } else {
      if (navigator.userAgent.toLowerCase().match(/chrome/) && location.origin.indexOf('https://') < 0) {
        alert('chrome下获取浏览器录音功能，因为安全性问题，需要在localhost或127.0.0.1或https下才能获取权限')
      } else {
        alert('无法获取浏览器录音功能，请升级浏览器或使用chrome')
      }
      this.audioContext && this.audioContext.close()
      return
    }
    // 获取浏览器录音权限成功的回调
    let getMediaSuccess = stream => {
      console.log('getMediaSuccess')
      // 创建一个用于通过JavaScript直接处理音频
      this.scriptProcessor = this.audioContext.createScriptProcessor(0, 1, 1)
      this.scriptProcessor.onaudioprocess = e => {
        // 去处理音频数据
        if (this.status === 'ing') {
          this.transWorker.postMessage(e.inputBuffer.getChannelData(0))
        }
      }
      // 创建一个新的MediaStreamAudioSourceNode 对象，使来自MediaStream的音频可以被播放和操作
      this.mediaSource = this.audioContext.createMediaStreamSource(stream)
      // 连接
      this.mediaSource.connect(this.scriptProcessor)
      this.scriptProcessor.connect(this.audioContext.destination)
      this.connectWebSocket()
    }

    let getMediaFail = (e) => {
      alert('请求麦克风失败')
      console.log(e)
      this.audioContext && this.audioContext.close()
      this.audioContext = undefined
      // 关闭websocket
      if (this.webSocket && this.webSocket.readyState === 1) {
        this.webSocket.close()
      }
    }
  }
  recorderStart() {
    if (!this.audioContext) {
      this.recorderInit()
    } else {
      this.audioContext.resume()
      this.connectWebSocket()
    }
  }
  // 暂停录音
  recorderStop() {
    // safari下suspend后再次resume录音内容将是空白，设置safari下不做suspend
    if (!(/Safari/.test(navigator.userAgent) && !/Chrome/.test(navigator.userAgen))) {
      this.audioContext && this.audioContext.suspend()
    }
    this.setStatus('end')
  }
  // 处理音频数据
  // transAudioData(audioData) {
  //   audioData = transAudioData.transaction(audioData)
  //   this.audioData.push(...audioData)
  // }
  // 对处理后的音频数据进行base64编码，
  toBase64(buffer) {
    var binary = ''
    var bytes = new Uint8Array(buffer)
    var len = bytes.byteLength
    for (var i = 0; i < len; i++) {
      binary += String.fromCharCode(bytes[i])
    }
    return window.btoa(binary)
  }
  // 向webSocket发送数据
  webSocketSend() {
    if (this.webSocket.readyState !== 1) {
      return
    }
    let audioData = this.audioData.splice(0, 1280)
    var params = {
      common: {
        app_id: this.appId,
      },
      business: {
        language: this.language, //小语种可在控制台--语音听写（流式）--方言/语种处添加试用
        domain: 'iat',
        accent: this.accent, //中文方言可在控制台--语音听写（流式）--方言/语种处添加试用
        vad_eos: 5000,
        dwa: 'wpgs', //为使该功能生效，需到控制台开通动态修正功能（该功能免费）
      },
      data: {
        status: 0,
        format: 'audio/L16;rate=16000',
        encoding: 'raw',
        audio: this.toBase64(audioData),
      },
    }
    this.webSocket.send(JSON.stringify(params))
    this.handlerInterval = setInterval(() => {
      // websocket未连接
      if (this.webSocket.readyState !== 1) {
        this.audioData = []
        clearInterval(this.handlerInterval)
        return
      }
      if (this.audioData.length === 0) {
        if (this.status === 'end') {
          this.webSocket.send(
            JSON.stringify({
              data: {
                status: 2,
                format: 'audio/L16;rate=16000',
                encoding: 'raw',
                audio: '',
              },
            })
          )
          this.audioData = []
          clearInterval(this.handlerInterval)
        }
        return false
      }
      audioData = this.audioData.splice(0, 1280)
      // 中间帧
      this.webSocket.send(
        JSON.stringify({
          data: {
            status: 1,
            format: 'audio/L16;rate=16000',
            encoding: 'raw',
            audio: this.toBase64(audioData),
          },
        })
      )
    }, 40)
  }
  result(resultData) {
    // 识别结束
    let jsonData = JSON.parse(resultData)
    if (jsonData.data && jsonData.data.result) {
      let data = jsonData.data.result
      let str = ''
      let resultStr = ''
      let ws = data.ws
      for (let i = 0; i < ws.length; i++) {
        str = str + ws[i].cw[0].w
      }
      // 开启wpgs会有此字段(前提：在控制台开通动态修正功能)
      // 取值为 "apd"时表示该片结果是追加到前面的最终结果；取值为"rpl" 时表示替换前面的部分结果，替换范围为rg字段
      if (data.pgs) {
        if (data.pgs === 'apd') {
          // 将resultTextTemp同步给resultText
          this.setResultText({
            resultText: this.resultTextTemp,
            resultTextTemp: undefined
          })
        }
        // 将结果存储在resultTextTemp中
        this.setResultText({
          resultText: undefined,
          resultTextTemp: this.resultText + str,
        })
      } else {
        this.setResultText({
          resultText: this.resultText + str,
          resultTextTemp: undefined
        })
      }
    }
    if (jsonData.code === 0 && jsonData.data.status === 2) {
      this.webSocket.close()
    }
    if (jsonData.code !== 0) {
      this.webSocket.close()
      console.log(`${jsonData.code}:${jsonData.message}`)
    }
  }
  start() {
    this.recorderStart()
    this.setResultText({ resultText: '', resultTextTemp: '' })
  }
  stop() {
    this.recorderStop()
  }
}

/********************* assets/js/transcode.worker.js******************** */
(function(){
  self.onmessage = function(e){
    transAudioData.transcode(e.data)
  }

  let transAudioData = {
    transcode(audioData) {
      let output = transAudioData.to16kHz(audioData)
      output = transAudioData.to16BitPCM(output)
      output = Array.from(new Uint8Array(output.buffer))
      self.postMessage(output)
      // return output
    },
    to16kHz(audioData) {
      var data = new Float32Array(audioData)
      var fitCount = Math.round(data.length * (16000 / 44100))
      var newData = new Float32Array(fitCount)
      var springFactor = (data.length - 1) / (fitCount - 1)
      newData[0] = data[0]
      for (let i = 1; i < fitCount - 1; i++) {
        var tmp = i * springFactor
        var before = Math.floor(tmp).toFixed()
        var after = Math.ceil(tmp).toFixed()
        var atPoint = tmp - before
        newData[i] = data[before] + (data[after] - data[before]) * atPoint
      }
      newData[fitCount - 1] = data[data.length - 1]
      return newData
    },
    to16BitPCM(input) {
      var dataLength = input.length * (16 / 8)
      var dataBuffer = new ArrayBuffer(dataLength)
      var dataView = new DataView(dataBuffer)
      var offset = 0
      for (var i = 0; i < input.length; i++, offset += 2) {
        var s = Math.max(-1, Math.min(1, input[i]))
        dataView.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7fff, true)
      }
      return dataView
    },
  }
})()