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yformula

v0.0.5

Published

Formula parser library

Readme

yformula

A simple and small formula parser library for JavaScript running on both of Server and Client (Browser).

Feature

  • Number String Boolean Array Object types.
  • + - * / ^ % arithmetic operations.
  • & | ~(xor) << >> bit operations.
  • ! && || ~~ logical operations.
  • = <> < > <= >= comparision operations.
  • E LN10 LN2 LOG10E LOG2E PI SQRT1_2 SQRT2 all Math constants.
  • NULL TRUE FALSE constants.
  • abs cos pow sqrt and so on, all Math functions.
  • Custom variables.
  • Custom functions.
  • Custom operations.
  • Parser Evaluator classes.
  • evaluate function returning runnable function.
  • Both of Server and Client (Browser).

License

Apache License 2.0

Usage

Install

$ npm install yformula

Quick start

Server

const { Option, Parser, Evaluator, evaluate } = require('yformula');

// Parser
const parser = new Parser();
parser.parse('6+3*4-12/2^3+(5-2)*7-17%11+8*sin(PI/180*30)').then(result => {
  console.log(result); // output 35.5
});

// Evaluator
const evaluator = new Evaluator('6+3*4-12/2^3+(5-2)*7-17%11+8*sin(PI/180*30)');
evaluator.calculate().then(result => {
  console.log(result); // output 35.5
});

// evaluate()
const option = Option();
const evaluated = evaluate('6+3*4-12/2^3+(5-2)*7-17%11+8*sin(PI/180*30)', option);
evaluated(option).then(result => {
  console.log(result); // output 35.5
});

Client (Browser)

<script src="path/to/yformula.js"></script>

<body>
    <label for="parser_answer">Parser</label>
    <input id="parser_answer" type="text"></input>
    <br>
    <label for="evaluator_answer">Evaluator</label>
    <input id="evaluator_answer" type="text"></input>
    <br>
    <label for="evaluate_answer">evaluate()</label>
    <input id="evaluate_answer" type="text"></input>
</body>

<script>
    // Parser
    const parser = new yformula.Parser();
    parser.parse('6+3*4-12/2^3+(5-2)*7-17%11+8*sin(PI/180*30)').then(result => {
        document.getElementById('parser_answer').value = result; // output 35.5
    });

    // Evaluator
    const evaluator = new yformula.Evaluator('6+3*4-12/2^3+(5-2)*7-17%11+8*sin(PI/180*30)');
    evaluator.calculate().then(result => {
        document.getElementById('evaluator_answer').value = result; // output 35.5
    });

    // evaluate()
    const evaluated = yformula.evaluate('6+3*4-12/2^3+(5-2)*7-17%11+8*sin(PI/180*30)');
    evaluated(yformula.Option({ operator: new yformula.Operator() })).then(result => {
        document.getElementById('evaluate_answer').value = result; // output 35.5
    });
</script>

API Reference

Appendix

Performance

Specification of operators