Sentiment is a Node.js module that uses the AFINN-111 wordlist to perform sentiment analysis on arbitrary blocks of input text. Sentiment provides serveral things:

• Performance (see benchmarks below)
• The ability to append and overwrite word / value pairs from the AFINN wordlist
• A build process that makes updating sentiment to future versions of the AFINN word list trivial

npm install sentiment

var sentiment = require('sentiment'); var r1 = sentiment('Cats are stupid.'); console.dir(r1); // Score: -2, Comparative: -0.666 var r2 = sentiment('Cats are totally amazing!'); console.dir(r2); // Score: 4, Comparative: 1

You can append and/or overwrite values from AFINN by simply injecting key/value pairs into a sentiment method call:

var sentiment = require('sentiment'); var result = sentiment('Cats are totally amazing!', { 'cats': 5, 'amazing': 2 }); console.dir(result); // Score: 7, Comparative: 1.75

The primary motivation for designing sentiment was performance. As such, it includes a benchmark script within the test directory that compares it against the Sentimental module which provides a nearly equivalent interface and approach. Based on these benchmarks, running on a MacBook Pro with Node 0.12.7, sentiment is twice as fast as alternative implementations:

sentiment (Latest) x 544,714 ops/sec ±0.83% (99 runs sampled) Sentimental (1.0.1) x 269,417 ops/sec ±1.06% (96 runs sampled)

To run the benchmarks yourself, simply:

make benchmark

npm test