Initial commit

lib/BufferLoader.ts

@@ -0,0 +1,57 @@
+import { useBufferStore } from '~/stores/buffer'
+
+export class BufferLoader {
+  context: AudioContext
+  urlList: string[]
+  onload: (bufferList: AudioBuffer[], urlList:string[]) => void
+  bufferList: AudioBuffer[]
+  loadCount: number
+
+  constructor (context: AudioContext, urlList: string[], callback: (bufferList: AudioBuffer[], urlList:string[]) => void) {
+    this.context = context
+    this.urlList = urlList
+    this.onload = callback
+    this.bufferList = new Array(urlList.length)
+    this.loadCount = 0
+  }
+
+  loadBuffer (url: string, index: number): void {
+    // Load buffer asynchronously
+    const request = new XMLHttpRequest()
+    request.open('GET', url, true)
+    request.responseType = 'arraybuffer'
+
+    request.onload = () => {
+      // Asynchronously decode the audio file data in request.response
+      const fileName = useBufferStore().extractFilename(url)
+
+      this.context.decodeAudioData(
+        request.response,
+        (buffer: AudioBuffer) => {
+          if (!buffer) {
+            alert('error decoding file data: ' + url)
+            return
+          }
+          this.bufferList[index] = buffer
+          if (++this.loadCount === this.urlList.length) { this.onload(this.bufferList, this.urlList) }
+        },
+        (_error) => {
+          // useNuxtApp().$logger.error('decodeAudioData error', error)
+        }
+      )
+      useBufferStore().saveBufferInIndexedDb(fileName, request.response)
+    }
+
+    request.onerror = () => {
+      alert('BufferLoader: XHR error')
+    }
+
+    request.send()
+  }
+
+  load (): void {
+    this.urlList.forEach((url, index) => {
+      this.loadBuffer(url, index)
+    })
+  }
+}