tinyexpr

Parse, compile and evaluate expressions in a safe sandboxed environment

Emscripten port and wrapper around native C TinyExpr library. Works in both Node.js and the browser. Generally slower than JS, but makes you worry less about alerts in user provided expressions

Installation

npm install -S tinyexpr

Usage

const { interp, compile } = require('tinyexpr')

• interp immidiately executes an expression and returns results

const res = interp('1 + 1') // -> 2

• compile takes an expression and an array of used variable names. Returns a JS function wrapping the compiled expression. Pass args in the same order as in variables array

const sqrt = compile('sqrt(x)', ['x'])
const res = sqrt(4) // -> 2

Work with arrays

Passing data between JS and WASM is a bottleneck, so if you need to iterate over an array, it's better to pass it to the compiled function directly, rather than calling the function from a JS loop. In such way iteration happens on a lower level and takes less time

wasm (in a loop): 216.668ms
wasm (array arg): 56.32ms

Supported functions

• addition (+), subtraction/negation (-), multiplication (*), division (/), exponentiation (^), modulus (%)
• abs, acos, asin, atan, atan2, ceil, cos, cosh, exp, floor, ln, log, log10, pow, sin, sinh, sqrt, tan, tanh, fac (factorials e.g. fac 5 == 120), ncr (combinations e.g. ncr(6,2) == 15), npr (permutations e.g. npr(6,2) == 30)
• constants pi and e

Read more about how the native TinyExpr library works: https://github.com/codeplea/tinyexpr/blob/master/README.md