decimal.js-formulas

Lightweight formula parser and evaluator for Decimal.js. It tokenizes input, builds an AST, and either compiles to an evaluator function or assembles a function from generated code. Internals are exposed for advanced use.

Install

bun add decimal.js-formulas decimal.js

pnpm add decimal.js-formulas decimal.js

npm i decimal.js-formulas decimal.js

Usage

Compiled evaluator (recommended):

import { createFormula } from "decimal.js-formulas/compiled";

const evalFn = createFormula("max(1, x) + 2 * 3");
evalFn({ x: 4 }); // Decimal(11)

Assembled evaluator (generated JS body, faster):

import { createFormula } from "decimal.js-formulas/assembled";

const evalFn = createFormula("(x + 2).pow(3) / 2");
evalFn({ x: 2 }); // Decimal(8)

You can type formula variables by passing a generic type to createFormula:

import { createFormula } from "decimal.js-formulas/compiled";

const myFormula = createFormula<{ x: number, y: number }>("x + 2 * y");
myFormula({ x: 1, y: 2 }); // Decimal(5)
myFormula({ x: 1 }); // Error: Missing required variable "y"

Internals

All internals are available by importing from decimal.js-formulas/internals. This includes:

• tokenizeFormula
• parseFormula
• compileFormula
• assembleFormula
• types and utility helpers

Testing

This project uses Bun’s test runner.

bun test

Notes

• Peer dependency decimal.js is required at runtime.