Jabr

A bidirectional, strictly-typed algebraic equation solver for TypeScript.

@morkg/jabr lets you define a single mathematical relationship and automatically solve for the missing value, using pattern matching and route-based evaluation.

Why Jabr

• Bidirectional formula execution
• Type-safe inputs and return values
• Zero any in runtime logic
• Works with partial variable input
• Built-in classic formulas for common physics and math problems

Installation

npm install @morkg/jabr

or

yarn add @morkg/jabr

Quick Start

Define a formula by listing variable names and providing route definitions. Each route evaluates only when the required inputs are available.

import jabr from "@morkg/jabr";

const speed = jabr("v", "d", "t")(({ v, d, t }, solve) => [
  solve([v, d, t], (v, d, t) => v === d / t),
  solve([d, t], (d, t) => d / t),
  solve([v, d], (v, d) => d / v),
  solve([v, t], (v, t) => v * t),
  solve(() => {
    throw new Error("Insufficient variables. Provide at least two values.");
  })
]);

const velocity = speed({ d: 100, t: 10 });
// 10

const distance = speed({ v: 10, t: 10 });
// 100

const valid = speed({ v: 10, d: 100, t: 10 });
// true

API

jabr(...variables)

Creates a formula builder for the provided variable names.

solver(routes)

The solve helper accepts one of two forms:

• solve([deps], callback) — runs when all deps are defined
• solve(() => ...) — fallback route when no other route matches

Built-in Formula Library

@morkg/jabr exports a collection of ready-to-use formulas:

• quadratic
• newton
• kineticEnergy
• pythagoras
• compoundInterest
• universalGravitation

import {
  quadratic,
  kineticEnergy,
  pythagoras,
  compoundInterest,
  universalGravitation
} from "@morkg/jabr";

Quadratic Formula

Solves $ax^2 + bx + c = 0$.

const roots = quadratic({ a: 1, b: -5, c: 6 });
// { x1: 3, x2: 2 }

Kinetic Energy

Calculates $E_k = \frac{1}{2}mv^2$.

const energy = kineticEnergy({ m: 10, v: 5 });
// 125

Pythagorean Theorem

Solves $c^2 = a^2 + b^2$.

const hypotenuse = pythagoras({ a: 3, b: 4 });
// 5

Compound Interest

Calculates compound growth over time.

const amount = compoundInterest({ p: 1000, r: 0.05, n: 1, t: 2 });

Universal Gravitation

Solves Newton's law of gravitation.

const force = universalGravitation({ m1: 5.97e24, m2: 7.35e22, r: 3.84e8 });

Notes

• This package is built for TypeScript-first workflows.
• The package exports both a default jabr factory and named formula helpers.

Contributing

Contributions, bug reports, and suggestions are welcome. Please open an issue or pull request at github.com/morkg/jabr.

License

MIT