PHP's var_export in JavaScript

How to use

You you can install via yarn add locutus and require this function via const var_export = require('locutus/php/var/var_export').

It is important to use a bundler that supports tree-shaking so that you only ship the functions that you actually use to your browser, instead of all of Locutus, which is massive. Examples are: Parcel, webpack, or rollup.js. For server-side use this is typically less of a concern.

Examples

Please note that these examples are distilled from test cases that automatically verify our functions still work correctly. This could explain some quirky ones.

#	code	expected result
1	var_export(null)	null
2	var_export({0: 'Kevin', 1: 'van', 2: 'Zonneveld'}, true)	"array (\n 0 => 'Kevin',\n 1 => 'van',\n 2 => 'Zonneveld',\n)"
3	var data = 'Kevin' var_export(data, true)	"'Kevin'"
4	var_export({0: 'Kevin', 1: 'van', 'lastName': 'Zonneveld'}, true)	"array (\n 0 => 'Kevin',\n 1 => 'van',\n 'lastName' => 'Zonneveld',\n)"
5	var_export([], true)	"array (\n)"
6	var_export({ test: [ 'a', 'b' ] }, true)	"array (\n 'test' =>\n array (\n 0 => 'a',\n 1 => 'b',\n ),\n)"

Here’s what our current JavaScript equivalent to PHP's var_export looks like.

module.exports = function var_export(mixedExpression, boolReturn) {
  //  discuss at: https://locutus.io/php/var_export/
  // original by: Philip Peterson
  // improved by: johnrembo
  // improved by: Brett Zamir (https://brett-zamir.me)
  //    input by: Brian Tafoya (https://www.premasolutions.com/)
  //    input by: Hans Henrik (https://hanshenrik.tk/)
  // bugfixed by: Brett Zamir (https://brett-zamir.me)
  // bugfixed by: Brett Zamir (https://brett-zamir.me)
  // bugfixed by: simivar (https://github.com/simivar)
  // bugfixed by: simivar (https://github.com/simivar)
  // bugfixed by: simivar (https://github.com/simivar)
  //   example 1: var_export(null)
  //   returns 1: null
  //   example 2: var_export({0: 'Kevin', 1: 'van', 2: 'Zonneveld'}, true)
  //   returns 2: "array (\n  0 => 'Kevin',\n  1 => 'van',\n  2 => 'Zonneveld',\n)"
  //   example 3: var data = 'Kevin'
  //   example 3: var_export(data, true)
  //   returns 3: "'Kevin'"
  //   example 4: var_export({0: 'Kevin', 1: 'van', 'lastName': 'Zonneveld'}, true)
  //   returns 4: "array (\n  0 => 'Kevin',\n  1 => 'van',\n  'lastName' => 'Zonneveld',\n)"
  //   example 5: var_export([], true)
  //   returns 5: "array (\n)"
  //   example 6: var_export({ test: [ 'a', 'b' ] }, true)
  //   returns 6: "array (\n  'test' =>\n  array (\n    0 => 'a',\n    1 => 'b',\n  ),\n)"

  const echo = require('../strings/echo')
  let retstr = ''
  let iret = ''
  let value
  let cnt = 0
  const x = []
  let i = 0
  let funcParts = []
  // We use the last argument (not part of PHP) to pass in
  // our indentation level
  const idtLevel = arguments[2] || 2
  let innerIndent = ''
  let outerIndent = ''
  const getFuncName = function (fn) {
    const name = /\W*function\s+([\w$]+)\s*\(/.exec(fn)
    if (!name) {
      return '(Anonymous)'
    }
    return name[1]
  }

  const _isNormalInteger = function (string) {
    const number = Math.floor(Number(string))
    return number !== Infinity && String(number) === string && number >= 0
  }

  const _makeIndent = function (idtLevel) {
    return new Array(idtLevel + 1).join(' ')
  }
  const __getType = function (inp) {
    let i = 0
    let match
    let types
    let cons
    let type = typeof inp
    if (type === 'object' && inp && inp.constructor && getFuncName(inp.constructor) === 'LOCUTUS_Resource') {
      return 'resource'
    }
    if (type === 'function') {
      return 'function'
    }
    if (type === 'object' && !inp) {
      // Should this be just null?
      return 'null'
    }
    if (type === 'object') {
      if (!inp.constructor) {
        return 'object'
      }
      cons = inp.constructor.toString()
      match = cons.match(/(\w+)\(/)
      if (match) {
        cons = match[1].toLowerCase()
      }
      types = ['boolean', 'number', 'string', 'array']
      for (i = 0; i < types.length; i++) {
        if (cons === types[i]) {
          type = types[i]
          break
        }
      }
    }
    return type
  }
  const type = __getType(mixedExpression)

  if (type === null) {
    retstr = 'NULL'
  } else if (type === 'array' || type === 'object') {
    outerIndent = _makeIndent(idtLevel - 2)
    innerIndent = _makeIndent(idtLevel)
    for (i in mixedExpression) {
      value = ' '
      const subtype = __getType(mixedExpression[i])
      if (subtype === 'array' || subtype === 'object') {
        value = '\n'
      }
      value += var_export(mixedExpression[i], 1, idtLevel + 2)
      i = _isNormalInteger(i) ? i : `'${i}'`
      x[cnt++] = innerIndent + i + ' =>' + value
    }
    if (x.length > 0) {
      iret = x.join(',\n') + ',\n'
    }
    retstr = outerIndent + 'array (\n' + iret + outerIndent + ')'
  } else if (type === 'function') {
    funcParts = mixedExpression.toString().match(/function .*?\((.*?)\) \{([\s\S]*)\}/)

    // For lambda functions, var_export() outputs such as the following:
    // '\000lambda_1'. Since it will probably not be a common use to
    // expect this (unhelpful) form, we'll use another PHP-exportable
    // construct, create_function() (though dollar signs must be on the
    // variables in JavaScript); if using instead in JavaScript and you
    // are using the namespaced version, note that create_function() will
    // not be available as a global
    retstr = "create_function ('" + funcParts[1] + "', '" + funcParts[2].replace(/'/g, "\\'") + "')"
  } else if (type === 'resource') {
    // Resources treated as null for var_export
    retstr = 'NULL'
  } else {
    retstr =
      typeof mixedExpression !== 'string'
        ? mixedExpression
        : "'" + mixedExpression.replace(/(["'])/g, '\\$1').replace(/\0/g, '\\0') + "'"
  }

  if (!boolReturn) {
    echo(retstr)
    return null
  }

  return retstr
}

A community effort

Not unlike Wikipedia, Locutus is an ongoing community effort. Our philosophy follows The McDonald’s Theory. This means that we assimilate first iterations with imperfections, hoping for others to take issue with-and improve them. This unorthodox approach has worked very well to foster fun and fruitful collaboration, but please be reminded to use our creations at your own risk. THE SOFTWARE IS PROVIDED "AS IS" has never been more true than for Locutus.

Now go and: [ View on GitHub | Edit on GitHub | View Raw ]

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