composr-core/src/lib/regexpGenerator.js

CompoSR core functions

'use strict'

var XRegExp = require('xregexp')

/**
 * Returns a regexp for a express route
 * @example
 * url = 'domain/your/phrase/:name/:param1?'; => regexp = '/domain/your/phrase/%s[/%s'
 * @param  {String} url
 * @return {String}
 */
function regexpUrl (url) {
  var pathParams = url.split('/')
  var EMPTY_PARAMS_REGEXP = '^$|^/$'

  var paramsLength = pathParams.length

  function isEmptyArgument () {
    return paramsLength === 1 && pathParams[0] === ''
  }

  function isOptionalArgument (item) {
    return item.indexOf('?') !== -1
  }

  function isParamArgument (item) {
    return item.indexOf(':') !== -1
  }

  // Empty args, regex for empty element
  if (isEmptyArgument()) {
    return EMPTY_PARAMS_REGEXP
  }

  var regexp = pathParams.reduce(function (prev, item, index) {
    var newValue = ''

    if (index !== 0) {
      // Theres a previous value, add a slash
      newValue = '\/'
    }

    if (isParamArgument(item)) {
      // Param can have any value, evaluate expression
      if (isOptionalArgument(item, index) && index === paramsLength - 1 && paramsLength !== 1) {
        newValue += '((?<' + item.replace(':', '').replace('?', '') + '>[\\w-._~:?#\\[\\]@!$&()*+,;=!\\sáéíóúàèìòùç]+)\/?)?'
      } else {
        newValue += '(?<' + item.replace(':', '').replace('?', '') + '>[\\w-._~:?#\\[\\]@!$&()*+,;=!\\sáéíóúàèìòùç]+)\/?'
      }
    } else {
      // Fixed value in the form of 'fixednameparam', replace the ? symbol in case it's an optional param
      newValue += item.replace('?', '')
    }

    if (isOptionalArgument(item, index)) {
      // If is an optional param, add ( )
      newValue = '(' + newValue + ')?'
    }

    if ((pathParams.length === 1 && isParamArgument(item)) || index === 0) {
      // Single param in the form of ':param'  or ':param?' requires indicator of start of the string
      newValue = '^\/?' + newValue
    }

    // Single param in the form of ':param' , 'param' or ':param?' requires indicator of end of the string
    if (index === paramsLength - 1) {
      if (!isParamArgument(item)) {
        newValue += '\/?'
      }
      newValue += '$'
    }

    return prev + newValue
  }, '')

  return regexp
}

function regexpReference (url) {
  var PARAMS_EXTRACTOR_REGEX = /:(\w+)\?*/g
  var params = url.match(PARAMS_EXTRACTOR_REGEX) || []
  var regexp = regexpUrl(url)

  params = params.map(function (param) {
    return param.replace(':', '')
  })

  return {
    params: params,
    regexp: regexp,
    xregexp: XRegExp(regexp)
  }
}

module.exports = {
  regexpUrl: regexpUrl,
  regexpReference: regexpReference
}