https://github.com/nimitzdev/logical-expression-parser

Logical expression parser written in JavaScript
https://github.com/nimitzdev/logical-expression-parser

Last synced: 12 months ago
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Logical expression parser written in JavaScript

• Host: GitHub
• URL: https://github.com/nimitzdev/logical-expression-parser
• Owner: NimitzDEV
• License: mit
• Created: 2018-12-06T12:29:43.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2023-04-21T16:35:16.000Z (about 3 years ago)
• Last Synced: 2025-05-07T04:48:50.283Z (12 months ago)
• Language: JavaScript
• Size: 9.77 KB
• Stars: 22
• Watchers: 1
• Forks: 6
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Logical Expression Parser

[![npm version](https://badge.fury.io/js/logical-expression-parser.svg)](https://badge.fury.io/js/logical-expression-parser)

This is a logical expression parser for JavaScript, it can parse a logical expression into a AST object and evaluates the result using your token checking function.

## Supported logical operators

1. `|` Or

1. `&` And

1. `!` Not

1. `()` Parentheses

## How it works

1. The parser parse and tokenize the expression, for example one of your function requires `REGISTED&(SPECIAL|INVITED)`

1. Parser then will pass `REGISTED`, `SPECIAL` and `INVITED` into your token checking function to get a boolean result

1. Finaly the parser will evaluates the final result

## Example

```javascript

const LEP = require('logical-expression-parser');

const REQUIREMENTS = 'REGISTED&(SPECIAL|INVITED)';

const LIST_A = ['REGISTED', 'INVITED'];

const LIST_B = ['SPECIAL', 'EXPERT'];

const RESULT_A = LEP.parse(REQUIREMENTS, t => LIST_A.indexOf(t) > -1);

const RESULT_B = LEP.parse(REQUIREMENTS, t => LIST_B.indexOf(t) > -1);

// RESULT_A: true

// RESULT_B: false

```