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josdejong
11.6K Stars 1.0K Forks Apache License 2.0 4.5K Commits 313 Opened issues

#### Description

An extensive math library for JavaScript and Node.js

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#### Contributors list

https://mathjs.org

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with different data types like numbers, big numbers, complex numbers, fractions, units, and matrices. Powerful and easy to use.

## Features

• Supports numbers, big numbers, complex numbers, fractions, units, strings, arrays, and matrices.
• Is compatible with JavaScript's built-in Math library.
• Contains a flexible expression parser.
• Does symbolic computation.
• Comes with a large set of built-in functions and constants.
• Can be used as a command line application as well.
• Runs on any JavaScript engine.
• Is easily extensible.
• Open source.

## Usage

Math.js can be used in both node.js and in the browser.

Install math.js using npm:

```npm install mathjs
```

Math.js can be used similar to JavaScript's built-in Math library. Besides that, math.js can evaluate expressions and supports chained operations.

```import {
atan2, chain, derivative, e, evaluate, log, pi, pow, round, sqrt
} from 'mathjs'

// functions and constants
round(e, 3)                    // 2.718
atan2(3, -3) / pi              // 0.75
log(10000, 10)                 // 4
sqrt(-4)                       // 2i
pow([[-1, 2], [3, 1]], 2)      // [[7, 0], [0, 7]]
derivative('x^2 + x', 'x')     // 2 * x + 1
// expressions
evaluate('12 / (2.3 + 0.7)')   // 4
evaluate('12.7 cm to inch')    // 5 inch
evaluate('sin(45 deg) ^ 2')    // 0.5
evaluate('9 / 3 + 2i')         // 3 + 2i
evaluate('det([-1, 2; 3, 1])') // -7
// chaining
chain(3)
.multiply(2)
.done()  // 14
```

See the Getting Started for a more detailed tutorial.

## Browser support

Math.js works on any ES5 compatible JavaScript engine: node.js, Chrome, Firefox, Safari, Edge, and IE11.

## Build

First clone the project from github:

```git clone git://github.com/josdejong/mathjs.git
cd mathjs
```

Install the project dependencies:

```npm install
```

Then, the project can be build by executing the build script via npm:

```npm run build
```

This will build ESM output, CommonJS output, and the bundle math.js from the source files and put them in the folder lib.

## Develop

When developing new features for mathjs, it is good to be aware of the following background information.

### Code

The code of

`mathjs`
is written in ES modules, and requires all files to have a real, relative path, meaning the files must have a
`*.js`

### Architecture

What mathjs tries to achieve is to offer an environment where you can do calculations with mixed data types, like multiplying a regular

`number`
with a
`Complex`
number or a
`BigNumber`
, and work with all of those in matrices. Mathjs also allows to add a new data type, like say
`BigInt`
, with little effort.

The solution that mathjs uses has two main ingredients:

• Typed functions. All functions are created using

`typed-function`
. This makes it easier to (dynamically) create and extend a single function with new data types, automatically do type conversions on function inputs, etc. So, if you create function multiply for two

`number`
s, you can extend it with support for multiplying two
`BigInts`
. If you define a conversion from
`BigInt`
to
`number`
, the typed-function will automatically allow you to multiply a
`BigInt`
with a
`number`
.
• Dependency injection. When we have a function

`multiply`
with support for
`BigInt`
, thanks to the dependency injection, other functions using
`multiply`
under the hood, like
`prod`
, will automatically support
`BigInt`
too. This also works the other way around: if you don't need the heavyweight
`multiply`
(which supports BigNumbers, matrices, etc), and you just need a plain and simple number support, you can use a lightweight implementation of
`multiply`
just for numbers, and inject that in
`prod`
and other functions.

At the lowest level, mathjs has immutable factory functions which create immutable functions. The core function

`math.create(...)`
creates a new instance having functions created from all passed factory functions. A mathjs instance is a collection of created functions. It contains a function like
`math.import`
to allow extending the instance with new functions, which can then be used in the expression parser.

### Build scripts

The build script currently generates two types of output:

• any, generate entry points to create full versions of all functions
• number: generating and entry points to create lightweight functions just supporting
`number`

For each function, an object is generated containing the factory functions of all dependencies of the function. This allows to just load a specific set of functions, and not load or bundle any other functionality. So for example, to just create function

`add`
you can do
`math.create(addDependencies)`
.

## Test

To execute tests for the library, install the project dependencies once:

```npm install
```

Then, the tests can be executed:

```npm test
```

```npm run test:browser
```

To run the tests remotely on BrowserStack, first set the environment variables

`BROWSER_STACK_USERNAME`
and
`BROWSER_STACK_ACCESS_KEY`
```npm run test:browserstack
```

To test code coverage of the tests:

```npm run coverage
```

To see the coverage results, open the generated report in your browser:

```./coverage/lcov-report/index.html
```

### Continuous integration testing

Continuous integration tests are run on Github Actions and BrowserStack every time a commit is pushed to github. Github Actions runs the tests for different versions of node.js, and BrowserStack runs the tests on all major browsers.

Thanks Github Actions and BrowserStack for the generous free hosting of this open source project!