Introducing MathFlow - A Robust Mathematical Expression Parser

Writing mathematical expressions in code shouldn’t feel like translating between two foreign languages. When you write 2x + 3(y - 1) on paper, why should you need to write 2*x + 3*(y - 1) in your code? MathFlow is a lightweight JavaScript library that bridges this gap, letting you write math the way mathematicians do and also provide you with a step-by-step solution.

Overview

MathFlow understands mathematical expressions in their natural form. It’s designed around a simple principle:

if you can write it on paper, you should be able to evaluate it in code.

import { evaluate } from "@mathflowjs/mathflow"

// write math naturally
evaluate("2x + 3(y - 1)") // implicit multiplication
evaluate("sin(pi/4)") // trigonometric functions
evaluate("y = x^2") // variables and assignments
evaluate("sqrt(16) + log(100)") // built-in functions

The library handles standard arithmetic, trigonometric functions (sin, cos, tan), logarithms, power operations, and more. It supports variable assignments, so you can build complex calculations step by step. Behind the scenes, MathFlow uses an Abstract Syntax Tree (AST) to parse expressions with proper operator precedence, ensuring that 2 + 3 * 4 correctly evaluates to 14, not 20.

Usage

MathFlow isn’t trying to be a computer algebra system or a full programming language. It has one job: evaluate mathematical expressions accurately and efficiently. This focused approach makes it perfect for:

Formula calculators where users input mathematical expressions
Educational applications that need to evaluate student-written formulas
Scientific computing interfaces that require mathematical notation
Configuration systems where formulas define behavior

The library is lightweight and has no dependencies, making it easy to integrate into any JavaScript project. Install it with npm:

npm install @mathflowjs/mathflow

Then use it immediately in your Node.js or browser applications. The API is intentionally simple and most use cases only need the evaluate() function.

Try it Yourself

Want to see MathFlow in action? Head over to mathflow.js.org where you’ll find complete documentation and an interactive playground. The playground lets you experiment with different expressions, see how they’re tokenized, and view the results in real-time.

Whether you’re building a scientific calculator, a math learning app, or just need to evaluate user-provided formulas, MathFlow provides a clean, intuitive solution. It respects mathematical conventions while being practical for real-world JavaScript development.

Check out the documentation to learn more, or dive straight into the code on GitHub. MathFlow is open source under the MIT license, and contributions are always welcome.

🟦 npm - @mathflowjs/mathflow 🟦 docs - mathflow.js.org 🟦 repo - github.com/mathflowjs/mathflow