lochungtin / node-exp-solver

Mathematical expression solver / Reverse Polish Notation calculator for NodeJS

Node Expression Solver

Mathematical expression solver / Reverse Polish Notation calculator for NodeJS

Features

• Solve infix-notated mathematical expressions
• Solve RPN expressions
• Converts infix-notated expressions to RPN
• Tokenize infix-notated expressions
  • From string to array
  • Able to handle negative numbers
  • Spacing independent

Install

With NPM:

npm install --save @enigmaoffline/node-exp-solver

Usage

const Solver = require('@enigmaoffline/node-exp-solver');

// Tokenization
console.log(Solver.tokenize('-1+2*(3-4)/5+(-6+-7)'));
// => [ '-1', '+', '2', '*', '(', '3', '-', '4', ')', '/', '5', '+', '(', '-6', '+', '-7', ')' ]
console.log(Solver.tokenize('1*2^3+3'));
// => [ '1', '*', '2', '^', '3', '+', '3' ]


// Infix to RPN
console.log(Solver.toRPN(Solver.tokenize('1+2*3')));
// => [ '1', '2', '3', '*', '+' ]


// Basic Solve
console.log(Solver.solve(Solver.tokenize('1+2*3')));
// => 7

// Solve RPN
console.log(Solver.solveRPN(Solver.toRPN(Solver.tokenize('-2+3^2+1'))));
// => 8

Next Steps

1. Ability to handle Min / Max functions
2. Ability to handle trig functions
3. Ability to handle log functions

LICENSE - MIT - Lo Chung Tin