PHP's var_export in JavaScript

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

module.exports = function var_export (mixedExpression, boolReturn) { // eslint-disable-line camelcase
// 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(new RegExp("'", '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
}
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How to use

You you can install via npm install locutus and require it via require('locutus/php/var/var_export'). You could also require the var module in full so that you could access var.var_export instead.

If you intend to target the browser, you can then use a module bundler such as Parcel, webpack, Browserify, or rollup.js. This can be important because Locutus allows modern JavaScript in the source files, meaning it may not work in all browsers without a build/transpile step. Locutus does transpile all functions to ES5 before publishing to npm.

A community effort

Not unlike Wikipedia, Locutus is an ongoing community effort. Our philosophy follows The McDonald’s Theory. This means that we don't consider it to be a bad thing that many of our functions are first iterations, which may still have their fair share of issues. We hope that these flaws will inspire others to come up with better ideas.

This way of working also means that we don't offer any production guarantees, and recommend to use Locutus inspiration and learning purposes only.

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.

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

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