Add existing code

src/lib/recorder.js

@@ -0,0 +1,110 @@
+import WavEncoder from './wav-encoder'
+import { convertTimeMMSS } from './utils'
+
+export default class {
+  constructor (options = {}) {
+    this.afterStop = options.afterStop
+    this.micFailed = options.micFailed
+
+    this.bufferSize = 4096
+    this.records    = []
+    this.samples    = []
+
+    this.isPause      = false
+    this.isRecording  = false
+
+    this.duration = 0
+    this.volume   = 0
+
+    this._duration = 0
+  }
+
+  start () {
+    navigator.mediaDevices.getUserMedia({audio: true})
+                          .then(this._micCaptured.bind(this))
+                          .catch(this._micError.bind(this))
+    this.isPause = false
+    this.isRecording = true
+  }
+
+  stop () {
+    this.stream.getTracks().forEach((track) => track.stop())
+    this.input.disconnect()
+    this.processor.disconnect()
+    this.context.close()
+
+    let encoder = new WavEncoder({
+      bufferSize: this.bufferSize,
+      sampleRate: this.context.sampleRate,
+      samples: this.samples
+    })
+
+    let audioBlob = encoder.getData()
+    let audioUrl = URL.createObjectURL(audioBlob)
+
+    this.samples = []
+
+    this.records.push({
+      blob: audioBlob,
+      url: audioUrl,
+      duration: convertTimeMMSS(this.duration)
+    })
+
+    this.isPause = false
+    this.isRecording = false
+    this._duration = 0
+    this.duration = 0
+
+    if (this.afterStop) {
+      this.afterStop()
+    }
+  }
+
+  pause () {
+    this.stream.getTracks().forEach((track) => track.stop())
+    this.input.disconnect()
+    this.processor.disconnect()
+    this.context.close()
+
+    this._duration = this.duration
+    this.isPause = true
+  }
+
+  recordList () {
+    return this.records
+  }
+
+  lastRecord () {
+    return this.records.slice(-1)
+  }
+
+  _micCaptured (stream) {
+    this.context = new AudioContext()
+    this.input = this.context.createMediaStreamSource(stream)
+    this.processor = this.context.createScriptProcessor(this.bufferSize, 1, 1)
+    this.duration = this._duration
+    this.stream = stream
+
+    this.processor.onaudioprocess = (ev) => {
+      let sample = ev.inputBuffer.getChannelData(0)
+      let sum    = 0.0
+
+      for (let i = 0; i < sample.length; ++i) {
+        sum += sample[i] * sample[i]
+      }
+
+      this.duration = parseFloat(this._duration) + parseFloat(this.context.currentTime.toFixed(2))
+      this.volume = Math.sqrt(sum / sample.length).toFixed(2)
+      this.samples.push(new Float32Array(sample))
+    }
+
+    this.input.connect(this.processor)
+    this.processor.connect(this.context.destination)
+  }
+
+  _micError (error) {
+    if (this.micFailed) {
+      this.micFailed(error)
+    }
+  }
+}