@repositive/query-parser

• Installation
• Available Serializers
• Usage

The purpose of this library is to transform a search string to a tokenized data structure that can be used to perform analysis on the search input or as an intermediate structure to translate the query into other DSLs or query structures.

Features:

• Basic boolean algebra operators (AND, OR, NOT)
  • Implicit intersections (AND) on non quoted spaces.
  • Logic grouping with parens

  (white or blue) flower not thistle

• Exact match between quoted strings on non predicated tokens.

  flower "white daisy"

• Predicated/Filtered search

  family:Asteraceae population:>100000 england

Installation

With npm:

$ npm i @repositive/query-parser

Available Serializers

• Natural Language String
• ElasticSearch 2.x

Usage

The library exposes the following functions:

Tree construction

• token: (str: string) => Token
• predicate: ({key: string, value: string}) => Predicate
• and: <L extends Node, R extends Node>({left: L, right: R}) => AND<L, R>
• or: <L extends Node, R extends Node>({left: L, right: R}) => OR<L, R>
• not: <N extends Node>(negated: N) => NOT<N>

Tools

• fold: <R>(node: Node, f: (node: Node, l: R, r: R) => R, R) => R
• filter: <R> (node: Node, f: (node: Node) => node is R) => R[]
• path: (node: Node, target: Node) => Node[]
• remove: (node: Node, target: Node) => Node
• replace: ({on: Node, target: Node, replacement: Node}) => Node

Parsing natural language string

• fromNatural: (str: string) => Node
  Parses the current string and returns a boolean binary tree representing the search.

Serialization

• toNatural: (tree: Node) => string
  Serializes a boolean binary tree into a string emulating how a human would write it.
• toElastic2: (tree: Node) => any
  Serializes the boolean binary tree into a elasticsearch 2.x query.

importQPfrom'npm:@repositive/query-parser';// var QP = require(`@repositive/query-parser`); non ES6/*** "fromNatural" will generate the following tree from "is:user Istar NOT profession:developer":* { * "_id": "6bd6c61f-eab6-43bc-81d2-97f96c7c5f0a", * "_type": "AND", * "left": { * "_id": "081c058a-e8cc-4ede-9637-6fd6593d5388", * "_type": "predicate", * "key": "is", * "relation": "=", * "value": "user" * }, * "right": { * "_id": "4719c7d4-965a-45cc-8132-87ed3acdc560", * "_type": "AND", * "left": { * "_id": "8c8fae87-3aeb-4298-8f29-baf4c761ca12", * "_type": "token", * "value": "Istar" * }, * "right": { * "_id": "b0b49e4a-c2cc-4954-bc1d-b68bad17f441", * "_type": "NOT", * "negated": { * "_id": "323596ca-24fa-4ec5-a7a5-0d4d1ed45645", * "_type": "predicate", * "key": "profession", * "relation": "=", * "value": "developer" * } * } * } * } */consttree=QP.fromNatural('is:user Istar NOT profession:developer')/** We can find the profession predicate using the filter function**/constprofession=QP.filter(tree,(n)=>n.key==='profession')[0];/*** If we remove the profession filter with "remove" we expect to end with the following tree:* {* value: 'AND',* right: { text: 'Istar' },* left: {predicate: 'is', text: 'user'}* }*/constprofessional=QP.remove(tree,profession);/*** Adding a new filter (attribute:awesome) to the three will return a new tree with the attribute inserted in the leftmost position* {* value: 'AND',* left: { predicate: 'attribute', text: 'awesome'},* right: {* value: 'AND',* right: { text: 'Istar' },* left: { predicate: 'is', text: 'user'}* }* }*/constawesome=QP.and({left: professional,right: QP.predicate({key: 'attribute',value: 'awesome'}));/*** The serialization value of the new tree using "toBoolString" resembles the text as a human would write it:* "is:user Istar attribute: awesome"*/constnewQueryString=QP.toNatural(awesome);