porter2  

Very fast JavaScript implementation of the porter2 English stemming algorithm.

$ npm install porter2

Usage

The package is simple: it has no dependencies and exports a single function named stem.

Import using CommonJS:

const { stem } = require('porter2')

Or, import using EcmaScript Modules (through interoperability with CommonJS):

import { stem } from 'porter2'

Use the stemmer:

const word = stem('animadversion')
console.log(word) //=> animadvers

This stemmer expects a lowercase English word.

TypeScript type declarations are included.

Benchmarks

Here is a comparison with some other libraries benchmarked over the 29.4k test suite in a hot loop (you probably should take it with a little grain of salt):

library	throughput (node)	throughput (bun)	slower
porter2 2.0.0	11157 kops/s	11092 kops/s	1.000×
stemr 1.0.0	958 kops/s	1194 kops/s	11.641×
wink-porter2-stemmer 1 2.0.1	325 kops/s	407 kops/s	34.319×

Here are libraries that implement the older porter version 1 (note the behavior is not identical):

library	throughput (node)	throughput (bun)	slower
porter-stemmer-js 2 1.1.2	3081 kops/s	3583 kops/s	3.621×
stemmer 3 2.0.1	2030 kops/s	1789 kops/s	5.496×
@stdlib/nlp-porter-stemmer 0.2.3	1588 kops/s	1523 kops/s	7.024×
porter-stemmer 0.9.1	902 kops/s	1245 kops/s	12.373×

The benchmark code is in bench/run.mjs (bench/all.mjs for all libraries). This was tested with Node.js v24.15.0 and bun v1.3.13 on Zen 3 (4.5 GHz boosted).

Footnotes

1. wink-porter2-stemmer is 99.97% porter2 compliant (fails on ' cases only) ↩

2. That one has similar goals and, surprisingly, was published just 3 days before this package! (And after the author started working on porter2.js.) ↩

3. ESM only ↩