quantize-number

Quantize a number

About

Quantization is an operation that takes some number and constrains it to a discrete set of numbers.

For instance, quantizing the value of 3 to the even numbers could yield either 2 or 4. If the value of 4 is desired, then this library calls that a "covering" algorithm. If the value of 2 is desired, then that is called a "fitting" algorithm.

This library provides a utility to quantize numbers using both types of algorithms.

Uses

Two use cases for quantization are varied, and include:

1. Drag-to-resize user interfaces
2. Infinite scroll algorithms

Caveats

This library is generally unsuitable for quantum physics applications, as it requires that the discrete set of numbers have even spacing between them.

Installation

The easiest way to install this library is through npm.

npm install quantize-number

Then, import or require it into your library.

// ES2015 syntax
import quantizeNumber from 'quantize-number';

// CJS syntax
var quantizeNumber = require('quantize-number');

This library exports UMD, so it works in the most popular JavaScript module environments, including ES2015, CommonJS, AMD, and also browser globals.

Usage

quantizeNumber( val, quantum [, options] )

• val: The number to be quantized
• quantum: The gap between the discrete set numbers
• options: There's currently only one option, cover, which accepts a Boolean value. This determines whether the algorithm is covering or fitting (see below).

Examples

quantizeNumber(9, 3) === 9;

quantizeNumber(10, 4) === 8;
quantizeNumber(10, 4, {
  cover: true
}) === 12;

quantizeNumber(-77, 25) === -75;

Covering vs. Fitting

The idea of covering vs. fitting is important to this library. Consider quantizing the value of 78 to a quantum of 25. There are two choices: 75 or 100. If you want the larger of the two choices, 100, then you want cover: true. Otherwise, you want cover: false.

The same works for the negative numbers, too. If we have -78 and we're quantizing it against 25 (or -25), then cover: true would return -100, whereas cover: false would return -50.