mathjs/docs/extend.md

Extend

The library can easily be extended with functions and variables using the import function. The function import accepts a filename or an object with functions and variables.

var math = require('mathjs');

// define new functions and variables
math.import({
    myvalue: 42,
    hello: function (name) {
        return 'hello, ' + name + '!';
    }
});

// defined functions can be used in both JavaScript as well as the parser
math.myvalue * 2;               // 84
math.hello('user');             // 'hello, user!'

var parser = math.parser();
parser.eval('myvalue + 10');    // 52
parser.eval('hello("user")');   // 'hello, user!'

External libraries like numbers.js and numeric.js can be imported as well. The libraries must be installed using npm:

npm install numbers
npm install numeric

The libraries can be easily imported into math.js using import. By default, existing functions will not be overwritten, and math.js will create a wrapper function around the imported functions which converts data types like Matrix to primitive types like Array.

var math = require('mathjs');

// import the numbers.js and numeric.js libraries into math.js
math.import('numbers');
math.import('numeric');

// use functions from numbers.js
math.fibonacci(7);                          // 13
math.eval('fibonacci(7)');                  // 13

// use functions from numeric.js
math.eval('eig([1, 2; 4, 3])').lambda.x;    // [5, -1]