README

Sieving

Query-Based Item-List Reduction for JavaScript

About

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"))

Installation

$ npm install sieving

Usage

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' ]

Examples

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" ])

Query Syntax

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     ::=  /^[$#%@&]$/                         // namesapce symbol
id         ::=  /^[a-zA-Z][a-zA-Z0-9-_]*$/          // namespace identifier

Application Programming Interface (API)

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?: {
                wrap:      boolean,  /*  whether to internally wrap items (default: true)  */
                nsIds:     string[], /*  list of allowed namespace identifier and namespace symbols (default: [])  */
                fieldId:   string,   /*  name of identifier field in items (default: "id")  */
                fieldPrio: string,   /*  name of priority field in items (default: "prio" ) */
                fieldNs:   string    /*  name of namespace field in items (default: "")  */
            }
        )

        /*  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)  */
                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?: {
                wrap:      boolean,  /*  whether to internally wrap items (default: true)  */
                nsIds:     string[], /*  list of allowed namespace identifier and namespace symbols (default: [])  */
                fieldId:   string,   /*  name of identifier field in items (default: "id")  */
                fieldPrio: string,   /*  name of priority field in items (default: "prio" ) */
                fieldNs:   string,   /*  name of namespace field in items (default: "")  */
                fuzzy:     boolean,  /*  whether to fuzzy match quoted and bare terms (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
}

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Usage no npm install needed!