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    1.0.16 • Public • Published


    A better English POS tagger written in JavaScript

    Installation and usage

    Install via NPM:

    npm i --save en-pos

    How to use

    const Tag = require("en-pos").Tag;
    var tags = new Tag(["this","is","my","sentence"])
    .initial() // initial dictionary and pattern based tagging
    .smooth() // further context based smoothing
    // ["DT","VBZ","PRP$","NN"]

    Annotation Specification

    Annotation Name Example
    NN Noun dog man
    NNS Plural noun dogs men
    NNP Proper noun London Alex
    NNPS Plural proper noun Smiths
    VB Base form verb be
    VBP Present form verb throw
    VBZ Present form (3rd person) throws
    VBG Gerund form verb throwing
    VBD Past tense verb threw
    VBN Past participle verb thrown
    MD Modal verb can shall will may must ought
    JJ Adjective big fast
    JJR Comparative adjective bigger
    JJS Superlative adjective biggest
    RB Adverb not quickly closely
    RBR Comparative adverb less-closely faster
    RBS Superlative adverb fastest
    DT Determiner the a some both
    PDT Predeterminer all quite
    PRP Personal Pronoun I you he she
    PRP$ Possessive Pronoun I you he she
    POS Possessive ending 's
    IN Preposition of by in
    PR Particle up off
    TO to to
    WDT Wh-determiner which that whatever whichever
    WP Wh-pronoun who whoever whom what
    WP$ Wh-possessive whose
    WRB Wh-adverb how where
    EX Expletive there there
    CC Coordinating conjugation & and nor or
    CD Cardinal Numbers 1 7 77 one
    LS List item marker 1 B C One
    UH Interjection ah oh oops
    FW Foreign Words viva mon toujours
    , Comma ,
    : Mid-sent punct : ; ...
    . Sent-final punct. . ! ?
    ( Left parenthesis ) } ]
    ) Right parenthesis ( { [
    # Pound sign #
    $ Currency symbols $ £ ¥
    SYM Other symbols + * / < >
    EM Emojis & emoticons :)

    Accuracy and performance


    • When smoothing is enabled: 96.43% accuracy (processing 132K tokens in 38 seconds)
    • When smoothing is disabled: 94.4% accuracy (processing 132K tokens in 3 seconds)

    As of 25 Jan 2017, this library scored 96.43% at the Penn Treebank test (0.3% away from being a state of the art tagger).

    Being written in JavaScript, I think it's safe to say that this is the most accurate JavaScript POS tagger, since the only JS library I know of is pos-js which when I tested on the same treebank scored 87.8%, though it was faster than my implementation when smoothing is enabled.

    However, if performance is what's you're after rather than accuracy, then you have the option to disable smoothing in this library and this will marginally increase performance making this library even faster than pos-js but with far better accuracy (94.4%).

    Building from source and testing

    • Build: tsc (requires typescript)
    • Test: node test/test.ts



    npm i en-pos

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