mathjs/src/expression/function/help.js

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 dif

'use strict'

const getSafeProperty = require('../../utils/customs').getSafeProperty

function factory (type, config, load, typed, math) {
  const docs = load(require('../embeddedDocs'))

  /**
   * Retrieve help on a function or data type.
   * Help files are retrieved from the documentation in math.expression.docs.
   *
   * Syntax:
   *
   *    math.help(search)
   *
   * Examples:
   *
   *    console.log(math.help('sin').toString())
   *    console.log(math.help(math.add).toString())
   *    console.log(math.help(math.add).toJSON())
   *
   * @param {Function | string | Object} search   A function or function name
   *                                              for which to get help
   * @return {Help} A help object
   */
  return typed('help', {
    'any': function (search) {
      let prop
      let name = search

      if (typeof search !== 'string') {
        for (prop in math) {
          // search in functions and constants
          if (math.hasOwnProperty(prop) && (search === math[prop])) {
            name = prop
            break
          }
        }

        /* TODO: implement help for data types
         if (!text) {
         // search data type
         for (prop in math.type) {
         if (math.type.hasOwnProperty(prop)) {
         if (search === math.type[prop]) {
         text = prop
         break
         }
         }
         }
         }
         */
      }

      const doc = getSafeProperty(docs, name)
      if (!doc) {
        throw new Error('No documentation found on "' + name + '"')
      }
      return new type.Help(doc)
    }
  })
}

exports.math = true // request access to the math namespace as 5th argument of the factory function
exports.name = 'help'
exports.factory = factory