1. vue-qrcode-reader

在浏览器端html中有一款依赖可以直接调用摄像头扫码，vue-qrcode-reader。
分别提供QrcodeStream、QrcodeDropZone、QrcodeCapture用来识别二维码。

QrcodeStream：调用摄像头扫码
QrcodeDropZone：将图片移到识别区域内识别二维码
QrcodeCapture：选择原生拍照或者图片到浏览器识别二维码。

2. 安装

npm install vue-qrcode-reader

3. QrcodeStream直接调用摄像头扫码

init方法是初始化调用摄像头，此时如果摄像头报错会有很多提示，请酌情处理
decode方法，当识别到二维码会把识别信息触发出来

<template>
  <div>
    <p class="error">{{ error }}</p>

    <p class="decode-result">Last result: <b>{{ result }}</b></p>

    <qrcode-stream @decode="onDecode" @init="onInit" />
  </div>
</template>

<script>
import { QrcodeStream } from 'vue-qrcode-reader'

export default {

  components: { QrcodeStream },

  data () {
    return {
      result: '',
      error: ''
    }
  },

  methods: {
    onDecode (result) {
      this.result = result
    },

    async onInit (promise) {
      try {
        await promise
      } catch (error) {
        if (error.name === 'NotAllowedError') {
          this.error = "ERROR: you need to grant camera access permission"
        } else if (error.name === 'NotFoundError') {
          this.error = "ERROR: no camera on this device"
        } else if (error.name === 'NotSupportedError') {
          this.error = "ERROR: secure context required (HTTPS, localhost)"
        } else if (error.name === 'NotReadableError') {
          this.error = "ERROR: is the camera already in use?"
        } else if (error.name === 'OverconstrainedError') {
          this.error = "ERROR: installed cameras are not suitable"
        } else if (error.name === 'StreamApiNotSupportedError') {
          this.error = "ERROR: Stream API is not supported in this browser"
        } else if (error.name === 'InsecureContextError') {
          this.error = `ERROR: Camera access is only permitted in secure context. 
          Use HTTPS or localhost rather than HTTP.`;
        } else {
          this.error = `ERROR: Camera error (${error.name})`;
        }
      }
    }
  }
}
</script>

<style scoped>
.error {
  font-weight: bold;
  color: red;
}
</style>

4. 针对部分IOS【Vue warn】错误

TypeError： Reflect.construct requires the first argument to be a constructor
在这里插入图片描述
我目前没有更好的解决办法，只能充分利用vue生命周期中的捕获错误处理 errorCaptured。

有个开发说新版本不支持的

5. QrcodeCapture用原生拍照或者直接选择图片识别

decode方法和QrcodeStream一致，如果识别到了二维码将触发该事件。

<template>
  <div>
    <p>
      Capture:
      <select v-model="selected">
        <option v-for="option in options" :key="option.text" :value="option">
          {{ option.text }}
        </option>
      </select>
    </p>

    <hr/>

    <p class="decode-result">Last result: <b>{{ result }}</b></p>

    <qrcode-capture @decode="onDecode" :capture="selected.value" />
  </div>
</template>

<script>
import { QrcodeCapture } from 'vue-qrcode-reader'

export default {

  components: { QrcodeCapture },

  data () {
    const options = [
      { text: "rear camera (default)", value: "environment" },
      { text: "front camera", value: "user" },
      { text: "force file dialog", value: false },
    ]

    return {
      result: '',
      options,
      selected: options[0]
    }
  },

  methods: {
    onDecode (result) {
      this.result = result
    }
  }
}
</script>