ECMAScript Function Generator for node.js

This thing generates an array of numbers in waveforms. Written by Karl Westin, now horribly rewritten by mo-g. Though this version is faster!

Usage example:

import {FixedPitch, Silence, Tones, Generators, LinearBend} from 'ecma-tonegenerator'

var fixed = new FixedPitch({frequency:1701,
                            volume: 0.4});
var fixedData = fixed.approximate({duration: 3000});

var bend = new LinearBend({startFrequency: Tones["B5"],
                           endFrequency: Tones["D6"],
                           bitDepth: 32,
                           sampleRate: 96000,
                           generator: Generators.square);
var bendData = bend.approximate({duration: 3000});

var silence = new Silence({bitDepth: 16});
var silenceData = silence.accurate({samples: 24000});

Constructor parameters

• frequency (or startFrequency and endFrequency for bends) frequency in Hz, or pass in a predefined note.
• sampleRate defaults to 16000, you do you.
• bitDepth defaults to 16, you do you.
• volume A number between 0 and 1. 1 is max volume, 0 is silence.
• generator controls the wave shape. Options are 'triangle', 'square', 'sine', 'saw'. You can also pass in a custom function.

volume and generator are unsupported on Silence.

Output Functions

There are two rendering functions, class.accurate() and class.approximate(). Silence only supports accurate(), LinearBend only supports approximate() and FixedPitch supports both.

The function will return the smallest Two's Complement Typed Array possible for your bit depth.

Output Function Parameters

• duration in milliseconds. This will return the shortest number of complete waveforms equal to or greater than the specified duration, in order to prevent clipping.
• samples will provide the exact number of samples requested, regardless of whether it's the middle of a wave or not.
• offset offsets the wave by the specified number of samples. This will typically cause clipping.

Only one size parameter (duration or samples) may be specified at once.

Known Issues

• The LinearBend class is very experimental and is barely usable for anything.
• the toString() override is not supported on all versions of nodejs.