Query-Based Item-List Reduction for JavaScript

Sieving is a JavaScript library for reducing/filtering a JavaScript list of items, based on a simple simple query language. It is intended to be used for item list filtering or item list searching purposes within Browser or Node.js environments. Internally, Sieving is based on a full-blown query parser, supports optional fuzzy matching and namespacing of items, and supports union, intersection and subtraction of the result sets.

A query like...

foo bar^ +baz -quux, baz

...on a result set basis and mathematically means...

(((MATCH("foo") ∩ BOOST(MATCH("bar"), 1)) ∪ MATCH("baz")) ∖ MATCH("quux")) ∪ MATCH("baz")

...or expressed in a functional way:

UNION(
    SUBTRACT(
        UNION(
            INTERSECT(
                MATCH("foo"),
                BOOST(MATCH("bar"), 1)),
            MATCH("baz")),
        MATCH("quux")),
    MATCH("baz"))

$ npm install sieving

const Sieving = require("sieving")

let items = [ "foo", "bar", "baz", "quux", "foo bar", "foo baz", "foo quux", "foo bar quux" ]

/*  step-by-step usage  */
let sieving = new Sieving()
sieving.parse("foo +bar -quux, baz^")
console.log(sieving.format())
console.log(sieving.dump())
let result = sieving.sieve(items)
console.log(result)

/*  all-in-one usage  */
result = Sieving.sieve(items, "foo +bar -quux, baz^")
console.log(result)

Output:

queries [1,1]
├── query [1,1]
│   ├── term (value: "foo", type: "bare") [1,1]
│   ├── term (op: "union", value: "bar", type: "bare") [1,5]
│   └── term (op: "subtraction", value: "quux", type: "bare") [1,10]
└── query [1,17]
    └── term (value: "baz", type: "bare", boost: 1) [1,17]

[ 'baz', 'foo', 'foo bar', 'foo baz', 'bar' ]
[ 'baz', 'foo', 'foo bar', 'foo baz', 'bar' ]

const { sieve }  = require("sieving")
const { expect } = require("chai")

let items = [ "foo", "bar", "baz", "quux", "foo bar baz quux" ]

expect(sieve(items, "foo"))  .deep.equal([ "foo", "foo bar baz quux" ])
expect(sieve(items, "fo?"))  .deep.equal([ "foo", "foo bar baz quux" ])
expect(sieve(items, "/fo./")).deep.equal([ "foo", "foo bar baz quux" ])
expect(sieve(items, "'foo'")).deep.equal([ "foo" ])

expect(sieve(items, "bax",  { fuzzy: true })).deep.equal([ "bar", "baz" ])
expect(sieve(items, "fox",  { fuzzy: true })).deep.equal([ "foo" ])
expect(sieve(items, "qxux", { fuzzy: true })).deep.equal([ "quux" ])

expect(sieve(items, "foo"))          .deep.equal([ "foo", "foo bar baz quux" ])
expect(sieve(items, "foo bar"))      .deep.equal([ "foo bar baz quux" ])
expect(sieve(items, "foo +bar"))     .deep.equal([ "foo", "foo bar baz quux", "bar" ])
expect(sieve(items, "foo +bar -baz")).deep.equal([ "foo", "bar" ])
expect(sieve(items, "foo, bar"))     .deep.equal([ "foo", "foo bar baz quux", "bar" ])
expect(sieve(items, "bar, foo"))     .deep.equal([ "bar", "foo bar baz quux", "foo" ])

The following is a symbolic grammar describing the supported query syntax. For more subtle details, see the actual PEG grammar of the underlying parser.

queries    ::=  query ("," query)*                  // union of queries
query      ::=  term (" " term)*                    // intersection of terms
term       ::=  operation? namespace? text boost?   // single query term
operation  ::=  "+" | "-"                           // force union or subtraction of term
namespace  ::=  symbol | id ":"                     // match against a particular namespace
text       ::=  quoted | regexp | glob | bareword   // four variants of the term
boost      ::=  "^" number?                         // optionally boost the results
quoted     ::=  /"(\\"|[^"])*"/ | /'(\\'|[^'])*'/   // double- or single-quoted term
regexp     ::=  /\/(\\\/|[^\/])*\//                 // regular expression term
glob       ::=  /.*[*?[\]{}].*/                     // glob-style term
bareword   ::=  /.+/                                // bareword term
number     ::=  /\d*\.\d+/ | /\d+/                  // floating or integer number
symbol     ::=  /^[$#%@&]$/                         // namespace symbol
id         ::=  /^[a-zA-Z][a-zA-Z0-9-_]*$/          // namespace identifier

The following is the API as a TypeScript declaration. See also the actual TypeScript definition file.

declare module "Sieving" {
    class Sieving {
        /*  create Sieving instance  */
        public constructor(
            options?: {
                fieldsVal: string[], /*  names of fields in items of type object (default: [ "value" ])  */
                fieldId:   string    /*  name of optional field of unique identifier in items of type object (default: "id")  */
            }
        )

        /*  parse query into an internal AST  */
        parse(
            query:         string,   /*  query string  */
            options?: {
                lts:       boolean,  /*  parse query string into LST (default: true)  */
                ast:       boolean   /*  parse query string into AST (default: true)  */
            }
        ): void

        /*  dump internal AST as text (for debugging purposes only)  */
        dump(
            colorize?:     boolean   /*  whether to colorize output (default: true)  */
        ): string

        /*  format internal AST into query string  */
        format(
           format:         string    /*  format of output (default "text", or "html", "xml" or "json")  */
        ): string

        /*  evaluate internal AST (for custom matching)  */
        evaluate(
            queryResults: (
                ns:        string,   /*  term namespace (default: "")  */
                type:      string,   /*  term type ("regexp", "glob", "squoted", "dquoted", or "bareword")  */
                value:     string    /*  term value  */
            ) => any[]
        ): any[]

        /*  sieve items by evaluating query with standard matching  */
        sieve(
            items: any[],            /*  list of items to sieve/filter  */
            options?: {
                fuzzy:     boolean,  /*  whether to fuzzy match quoted and bare terms (default: false)  */
                nocase:    boolean,  /*  whether to match case-insensitive (default: false)  */
                maxLS:     number,   /*  maximum Levenshtein distance for fuzzy matching (default: 2)  */
                minDC:     number    /*  minimum Dice-Coefficient for fuzzy matching (default: 0.50)  */
            }
        ): any[]

        /*  sieve items by evaluating query with standard matching (stand-alone)  */
        static sieve(
            items: any[],            /*  list of items to sieve/filter  */
            query: string,           /*  query string  */
            options?: {
                fieldsVal: string[], /*  names of fields in items of type object (default: [ "value" ])  */
                fieldId:   string    /*  name of optional field of unique identifier in items of type object (default: "id")  */
                fuzzy:     boolean,  /*  whether to fuzzy match quoted and bare terms (default: false)  */
                nocase:    boolean,  /*  whether to match case-insensitive (default: false)  */
                maxLS:     number,   /*  maximum Levenshtein distance for fuzzy matching (default: 2)  */
                minDC:     number    /*  minimum Dice-Coefficient for fuzzy matching (default: 0.50)  */
                debug:     boolean   /*  whether to dump the internal AST to stdout  */
            }
        ): any[]
    }
    export = Sieving
}

Copyright © 2018-2024 Dr. Ralf S. Engelschall (http://engelschall.com/)

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