TypeError: Cannot read property 'isPaused' of null

Question

I'm trying to use wavesurfer.js in my vue front-end app. After I get the link to the audio file from the backend I get this error:

wavesurfer.js?8896:5179 Uncaught (in promise) TypeError: Cannot read property 'isPaused' of null
    at WaveSurfer.empty (wavesurfer.js?8896:5179)
    at WaveSurfer.load (wavesurfer.js?8896:4852)
    at _callee$ (GameScreen.vue?dcce:42)
    at tryCatch (runtime.js?96cf:63)
    at Generator.invoke [as _invoke] (runtime.js?96cf:293)
    at Generator.eval [as next] (runtime.js?96cf:118)
    at asyncGeneratorStep (asyncToGenerator.js?1da1:3)
    at _next (asyncToGenerator.js?1da1:25)
    at eval (asyncToGenerator.js?1da1:32)
    at new Promise (<anonymous>)

This is the code I'm using in my vue component

<script>
import axios from 'axios';
import wavesurfer from 'wavesurfer.js';

export default {
  name: 'GameScreen',
  data(){
    return {
      isLoading: true,
    }
  },
  mounted(){
    this.initAudio();
  },
  methods: {
    initAudio(){
      axios.get('http://localhost:6060/track').then( async (response) => {
        console.log(response.data);
        
        const waveform = new wavesurfer({
          container: this.$refs.wave,
          color: 'violet',
          backend: 'MediaElement'
        });
        
        await waveform.load(response.data);

        await waveform.on('ready', () => {
          this.isLoading = false;
          //waveform.play();
        });

        console.log(waveform);
      });
    }
  }
}
</script>

Is there any error in the code or something I can do to fix this?

UPDATE

The question is closed, I wanted to post the solution but not possible. Anyway the problem was with a typo I've made when the library is instantiated. I forget to call the create method. to instantiate correctly WaveSurfer the syntax is new WaveSurfer.create({...}) and not only new WaveSurfer({})

Thank you all for the help.

Answer 1

I realise this is an older question but I ran into this the other day. It was happening when a client navigated away from the page containing the Wavesurfer component/element. I ended up doing this to capture the event:

    let firstLoadFailure = false;
    try {
        const response = await fetch(this.callUrl);

        const blob = await response.blob();
        const blobUrl = URL.createObjectURL(blob);

        this.wavesurfer.load(blobUrl);
    } catch (error) {
        firstLoadFailure = true;
    }

    if (firstLoadFailure) {
        try {
            this.wavesurfer.load(this.callUrl);
        } catch {
            // nothing more we can do
        }
    }

Hopefully this will help anyone else who is coming across it