sample-manager

Create, load and keep track of samples

install

npm install sample-manager

creating the manager

To create the SampleManager, you need an AudioContext instance, a basepath where the sample-files are located and a default file extension.

import SampleManager from 'sample-manager';

const context = new AudioContext();
const manager = new SampleManager(context, 'path/to/samples', 'mp3');

adding samples

After this, you can add samples to the manager by using the addSample or addSamples method, which both need objects that adhere to the ICreateSample interface.

interface ICreateSample {
  name: string; // name (will be used as filename when no filename is supplied)
  fileName?: string; // can be used to use another filename than the name
  extension?: string; // forces an extension for this sample
  path?: string; // appends a path to the basepath
  data?: any; // optional data, for example to put samples in a group
}

Only the name property is mandatory, all others are optional. The name can be anything but will be used as filename when the fileName property is not set.

const samples = [
  {
    name: 'sample1' // when extension is 'mp3', this will load sample1.mp3
  },
  {
    name: 'sample2',
    extension: 'mp3' // will always load as mp3, and ignore the extension in the constructor
  },
  {
    name: 'sample3',
    fileName: 'sample3.v11.final2' // will not use the name to load the file
  },
  {
    name: 'car',
    path: 'car-sounds/' // will be appended to the basepath when loading
  },
]

Extensions (.mp3, .wav) should never be added to the name (when using name as filename) or filename, since the extension supplied in the manager's contructor will always be appended when loading.

When you have a list of these objects, you can add them to the SampleManager instance:

manager.addSamples(samples);

So when you don't have any special exceptions regarding path, filename or extension, you can just use the name field. Samples can then be quickly added like so:

const list = ['sample1', 'sample2'].map(name => ({name}));
manager.addSamples(list);

Sample names should be unique, adding a name that already exists will throw an error.

sample objects

After adding, all objects will be converted to the ISample interface, which extends ICreateSample and adds two properties: audioBuffer and fileSize (which default to null and -1 but will have proper data once the sample is loaded). It also makes the fileName property no longer optional (will be either the name or fileName from the original object).

interface ISample extends ICreateSample {
  audioBuffer: AudioBuffer;
  fileSize: number;
  fileName: string;
}

loading samples

When samples have been added, you can load them using the loadAllSamples method, which returns a promise.

manager.loadAllSamples().then(() => {
   // done
 })

If you want to load only a subset, you can refer to them by their name:

manager.loadSamplesByName(['bird', 'car']);

Both the loadAllSamples and loadSamplesByName method accept an optional callback to track the overall load progress.

manager.loadAllSamples(progress => {});

manager.loadSamplesByName(['bird', 'car'], progress => {});

Note that this callback will not be fired at all during decoding (which happens after a file is loaded). This may not be noticable for smaller files, but when you have files containing many minutes of audio the progress will not change for a while.

retrieving samples

const sample = manager.getSampleByName('kickdrum');
const samples = manager.getAllSamples();