rimath
Version:
Math Expression Evaluator
36 lines (23 loc) • 885 B
Markdown
RiMath is a small math expression evaluator in JavaScript. It uses the
[](https://en.wikipedia.org/wiki/Shunting-yard_algorithm) to convert
expressions to [Reverse Polish
Notation](https://en.wikipedia.org/wiki/Reverse_Polish_notation).
This code is battle-tested and has been in use since 2013 at [Turnkey
Telemetry](https://turnkeytelemetry.com/), both server-side and client-side.
```
var rimath = require('./rimath.js');
//Basic usage
var expr = rimath.compile("100+5*2");
console.log(expr()); //110
//Call external function
var triple = function(s) {s.push(s.pop()*3);};
var funcs = {trip: [1, triple]};
expr = rimath.compile("trip(100)", funcs);
console.log(expr()); //300
//Detect error (unbalanced paran)
expr = rimath.compile("1+(4*2");
console.log(expr); //{text: '1+(4*2', index: 6, token: '', type: 'paren'}
```