mathjs/src/function/string/print.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

import { format } from '../../utils/string'
import { isString } from '../../utils/is'
import { factory } from '../../utils/factory'

const name = 'print'
const dependencies = ['typed']

export const createPrint = /* #__PURE__ */ factory(name, dependencies, ({ typed }) => {
  /**
   * Interpolate values into a string template.
   *
   * Syntax:
   *
   *     math.print(template, values)
   *     math.print(template, values, precision)
   *     math.print(template, values, options)
   *
   * Example usage:
   *
   *     // the following outputs: 'Lucy is 5 years old'
   *     math.print('Lucy is $age years old', {age: 5})
   *
   *     // the following outputs: 'The value of pi is 3.141592654'
   *     math.print('The value of pi is $pi', {pi: math.pi}, 10)
   *
   *     // the following outputs: 'hello Mary! The date is 2013-03-23'
   *     math.print('Hello $user.name! The date is $date', {
   *       user: {
   *         name: 'Mary',
   *       },
   *       date: new Date(2013, 2, 23).toISOString().substring(0, 10)
   *     })
   *
   *     // the following outputs: 'My favorite fruits are apples and bananas !'
   *     math.print('My favorite fruits are $0 and $1 !', [
   *       'apples',
   *       'bananas'
   *     ])
   *
   * See also:
   *
   *     format
   *
   * @param {string} template           A string containing variable placeholders.
   * @param {Object | Array | Matrix}   values An object or array containing variables
   *                                    which will be filled in in the template.
   * @param {number | Object} [options] Formatting options,
   *                                    or the number of digits to format numbers.
   *                                    See function math.format for a description
   *                                    of all options.
   * @return {string} Interpolated string
   */
  return typed(name, {
    // note: Matrix will be converted automatically to an Array
    'string, Object | Array': _print,
    'string, Object | Array, number | Object': _print
  })
})

/**
 * Interpolate values into a string template.
 * @param {string} template
 * @param {Object} values
 * @param {number | Object} [options]
 * @returns {string} Interpolated string
 * @private
 */
function _print (template, values, options) {
  return template.replace(/\$([\w.]+)/g, function (original, key) {
    const keys = key.split('.')
    let value = values[keys.shift()]
    while (keys.length && value !== undefined) {
      const k = keys.shift()
      value = k ? value[k] : value + '.'
    }

    if (value !== undefined) {
      if (!isString(value)) {
        return format(value, options)
      } else {
        return value
      }
    }

    return original
  }
  )
}