mathjs/src/function/unit/to.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'

function factory (type, config, load, typed) {
  const latex = require('../../utils/latex')

  const matrix = load(require('../../type/matrix/function/matrix'))

  const algorithm13 = load(require('../../type/matrix/utils/algorithm13'))
  const algorithm14 = load(require('../../type/matrix/utils/algorithm14'))

  /**
   * Change the unit of a value.
   *
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.to(x, unit)
   *
   * Examples:
   *
   *    math.to(math.unit('2 inch'), 'cm')                   // returns Unit 5.08 cm
   *    math.to(math.unit('2 inch'), math.unit(null, 'cm'))  // returns Unit 5.08 cm
   *    math.to(math.unit(16, 'bytes'), 'bits')              // returns Unit 128 bits
   *
   * See also:
   *
   *    unit
   *
   * @param {Unit | Array | Matrix} x     The unit to be converted.
   * @param {Unit | Array | Matrix} unit  New unit. Can be a string like "cm"
   *                                      or a unit without value.
   * @return {Unit | Array | Matrix} value with changed, fixed unit.
   */
  const to = typed('to', {

    'Unit, Unit | string': function (x, unit) {
      return x.to(unit)
    },

    'Matrix, Matrix': function (x, y) {
      // SparseMatrix does not support Units
      return algorithm13(x, y, to)
    },

    'Array, Array': function (x, y) {
      // use matrix implementation
      return to(matrix(x), matrix(y)).valueOf()
    },

    'Array, Matrix': function (x, y) {
      // use matrix implementation
      return to(matrix(x), y)
    },

    'Matrix, Array': function (x, y) {
      // use matrix implementation
      return to(x, matrix(y))
    },

    'Matrix, any': function (x, y) {
      // SparseMatrix does not support Units
      return algorithm14(x, y, to, false)
    },

    'any, Matrix': function (x, y) {
      // SparseMatrix does not support Units
      return algorithm14(y, x, to, true)
    },

    'Array, any': function (x, y) {
      // use matrix implementation
      return algorithm14(matrix(x), y, to, false).valueOf()
    },

    'any, Array': function (x, y) {
      // use matrix implementation
      return algorithm14(matrix(y), x, to, true).valueOf()
    }
  })

  to.toTex = {
    2: `\\left(\${args[0]}${latex.operators['to']}\${args[1]}\\right)`
  }

  return to
}

exports.name = 'to'
exports.factory = factory