logical-expression-parser

Logical expression parser and evaluates result, suitable for permissions management

Usage no npm install needed!

<script type="module">
  import logicalExpressionParser from 'https://cdn.skypack.dev/logical-expression-parser';
</script>

README

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
  2. & And
  3. ! Not
  4. () Parentheses

How it works

  1. The parser parse and tokenize the expression, for example one of your function requires REGISTED&(SPECIAL|INVITED)
  2. Parser then will pass REGISTED, SPECIAL and INVITED into your token checking function to get a boolean result
  3. Finaly the parser will evaluates the final result

Example

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