Tests if regex matches all valid ES6 import syntaxes. https://github.com/facebook/react-native/pull/386

test-es6-imports.js

//
// Tests if regular expression matches all valid ES6 import syntaxes.
//
// ES6 Language Specification Reference:
//   https://people.mozilla.org/~jorendorff/es6-draft.html#sec-imports
//

const ES6_IMPORT_REGEX = /\bimport\s+(?:.+\s+from\s+)?[\'"]([^"\']+)["\']/g;

const VALID_ES6_IMPORT_SYNTAXES = [
  "import 'module' ;",
  "import Default from 'module' ;",
  "import * as All from 'module' ;",
  "import { } from 'module' ;",
  "import { Foo } from 'module' ;",
  "import { Foo , } from 'module' ;",
  "import { Foo as Bar } from 'module' ;",
  "import { Foo as Bar , } from 'module' ;",
  "import { Foo , Bar } from 'module' ;",
  "import { Foo , Bar , } from 'module' ;",
  "import { Foo as Bar , Baz } from 'module' ;",
  "import { Foo as Bar , Baz , } from 'module' ;",
  "import { Foo , Bar as Baz } from 'module' ;",
  "import { Foo , Bar as Baz , } from 'module' ;",
  "import { Foo as Bar , Baz as Qux } from 'module' ;",
  "import { Foo as Bar , Baz as Qux , } from 'module' ;",
  "import { Foo , Bar, Baz } from 'module' ;",
  "import { Foo , Bar, Baz , } from 'module' ;",
  "import { Foo as Bar , Baz , Qux } from 'module' ;",
  "import { Foo as Bar , Baz , Qux , } from 'module' ;",
  "import { Foo , Bar as Baz , Qux } from 'module' ;",
  "import { Foo , Bar as Baz , Qux , } from 'module' ;",
  "import { Foo , Bar , Baz as Qux } from 'module' ;",
  "import { Foo , Bar , Baz as Qux , } from 'module' ;",
  "import { Foo as Bar , Baz as Qux , Norf } from 'module' ;",
  "import { Foo as Bar , Baz as Qux , Norf , } from 'module' ;",
  "import { Foo as Bar , Baz , Qux as Norf } from 'module' ;",
  "import { Foo as Bar , Baz , Qux as Norf , } from 'module' ;",
  "import { Foo , Bar as Baz , Qux as Norf } from 'module' ;",
  "import { Foo , Bar as Baz , Qux as Norf , } from 'module' ;",
  "import { Foo as Bar , Baz as Qux , Norf as Enuf } from 'module' ;",
  "import { Foo as Bar , Baz as Qux , Norf as Enuf , } from 'module' ;",
  "import Default , * as All from 'module' ;",
  "import Default , { } from 'module' ;",
  "import Default , { Foo } from 'module' ;",
  "import Default , { Foo , } from 'module' ;",
  "import Default , { Foo as Bar } from 'module' ;",
  "import Default , { Foo as Bar , } from 'module' ;",
  "import Default , { Foo , Bar } from 'module' ;",
  "import Default , { Foo , Bar , } from 'module' ;",
  "import Default , { Foo as Bar , Baz } from 'module' ;",
  "import Default , { Foo as Bar , Baz , } from 'module' ;",
  "import Default , { Foo , Bar as Baz } from 'module' ;",
  "import Default , { Foo , Bar as Baz , } from 'module' ;",
  "import Default , { Foo as Bar , Baz as Qux } from 'module' ;",
  "import Default , { Foo as Bar , Baz as Qux , } from 'module' ;",
  "import Default , { Foo , Bar, Baz } from 'module' ;",
  "import Default , { Foo , Bar, Baz , } from 'module' ;",
  "import Default , { Foo as Bar , Baz , Qux } from 'module' ;",
  "import Default , { Foo as Bar , Baz , Qux , } from 'module' ;",
  "import Default , { Foo , Bar as Baz , Qux } from 'module' ;",
  "import Default , { Foo , Bar as Baz , Qux , } from 'module' ;",
  "import Default , { Foo , Bar , Baz as Qux } from 'module' ;",
  "import Default , { Foo , Bar , Baz as Qux , } from 'module' ;",
  "import Default , { Foo as Bar , Baz as Qux , Norf } from 'module' ;",
  "import Default , { Foo as Bar , Baz as Qux , Norf , } from 'module' ;",
  "import Default , { Foo as Bar , Baz , Qux as Norf } from 'module' ;",
  "import Default , { Foo as Bar , Baz , Qux as Norf , } from 'module' ;",
  "import Default , { Foo , Bar as Baz , Qux as Norf } from 'module' ;",
  "import Default , { Foo , Bar as Baz , Qux as Norf , } from 'module' ;",
  "import Default , { Foo as Bar , Baz as Qux , Norf as NoMore } from 'module' ;",
  "import Default , { Foo as Bar , Baz as Qux , Norf as NoMore , } from 'module' ;",
  'import "module" ;',
  'import Default from "module" ;',
  'import * as All from "module" ;',
  'import { } from "module" ;',
  'import { Foo } from "module" ;',
  'import { Foo , } from "module" ;',
  'import { Foo as Bar } from "module" ;',
  'import { Foo as Bar , } from "module" ;',
  'import { Foo , Bar } from "module" ;',
  'import { Foo , Bar , } from "module" ;',
  'import { Foo as Bar , Baz } from "module" ;',
  'import { Foo as Bar , Baz , } from "module" ;',
  'import { Foo , Bar as Baz } from "module" ;',
  'import { Foo , Bar as Baz , } from "module" ;',
  'import { Foo as Bar , Baz as Qux } from "module" ;',
  'import { Foo as Bar , Baz as Qux , } from "module" ;',
  'import { Foo , Bar, Baz } from "module" ;',
  'import { Foo , Bar, Baz , } from "module" ;',
  'import { Foo as Bar , Baz , Qux } from "module" ;',
  'import { Foo as Bar , Baz , Qux , } from "module" ;',
  'import { Foo , Bar as Baz , Qux } from "module" ;',
  'import { Foo , Bar as Baz , Qux , } from "module" ;',
  'import { Foo , Bar , Baz as Qux } from "module" ;',
  'import { Foo , Bar , Baz as Qux , } from "module" ;',
  'import { Foo as Bar , Baz as Qux , Norf } from "module" ;',
  'import { Foo as Bar , Baz as Qux , Norf , } from "module" ;',
  'import { Foo as Bar , Baz , Qux as Norf } from "module" ;',
  'import { Foo as Bar , Baz , Qux as Norf , } from "module" ;',
  'import { Foo , Bar as Baz , Qux as Norf } from "module" ;',
  'import { Foo , Bar as Baz , Qux as Norf , } from "module" ;',
  'import { Foo as Bar , Baz as Qux , Norf as NoMore } from "module" ;',
  'import { Foo as Bar , Baz as Qux , Norf as NoMore , } from "module" ;',
  'import Default , * as All from "module" ;',
  'import Default , { } from "module" ;',
  'import Default , { Foo } from "module" ;',
  'import Default , { Foo , } from "module" ;',
  'import Default , { Foo as Bar } from "module" ;',
  'import Default , { Foo as Bar , } from "module" ;',
  'import Default , { Foo , Bar } from "module" ;',
  'import Default , { Foo , Bar , } from "module" ;',
  'import Default , { Foo as Bar , Baz } from "module" ;',
  'import Default , { Foo as Bar , Baz , } from "module" ;',
  'import Default , { Foo , Bar as Baz } from "module" ;',
  'import Default , { Foo , Bar as Baz , } from "module" ;',
  'import Default , { Foo as Bar , Baz as Qux } from "module" ;',
  'import Default , { Foo as Bar , Baz as Qux , } from "module" ;',
  'import Default , { Foo , Bar, Baz } from "module" ;',
  'import Default , { Foo , Bar, Baz , } from "module" ;',
  'import Default , { Foo as Bar , Baz , Qux } from "module" ;',
  'import Default , { Foo as Bar , Baz , Qux , } from "module" ;',
  'import Default , { Foo , Bar as Baz , Qux } from "module" ;',
  'import Default , { Foo , Bar as Baz , Qux , } from "module" ;',
  'import Default , { Foo , Bar , Baz as Qux } from "module" ;',
  'import Default , { Foo , Bar , Baz as Qux , } from "module" ;',
  'import Default , { Foo as Bar , Baz as Qux , Norf } from "module" ;',
  'import Default , { Foo as Bar , Baz as Qux , Norf , } from "module" ;',
  'import Default , { Foo as Bar , Baz , Qux as Norf } from "module" ;',
  'import Default , { Foo as Bar , Baz , Qux as Norf , } from "module" ;',
  'import Default , { Foo , Bar as Baz , Qux as Norf } from "module" ;',
  'import Default , { Foo , Bar as Baz , Qux as Norf , } from "module" ;',
  'import Default , { Foo as Bar , Baz as Qux , Norf as Enuf } from "module" ;',
  'import Default , { Foo as Bar , Baz as Qux , Norf as Enuf , } from "module" ;',
];

VALID_ES6_IMPORT_SYNTAXES.forEach((code) => {
  let deps = [];
  code.replace(ES6_IMPORT_REGEX, function (match, dep) {
    deps.push(dep);
  });
  console.log(`[${deps.length ? 'PASS' : 'FAIL'}] ${code}`);
});

test-result.txt

[PASS] import 'module' ;
[PASS] import Default from 'module' ;
[PASS] import * as All from 'module' ;
[PASS] import { } from 'module' ;
[PASS] import { Foo } from 'module' ;
[PASS] import { Foo , } from 'module' ;
[PASS] import { Foo as Bar } from 'module' ;
[PASS] import { Foo as Bar , } from 'module' ;
[PASS] import { Foo , Bar } from 'module' ;
[PASS] import { Foo , Bar , } from 'module' ;
[PASS] import { Foo as Bar , Baz } from 'module' ;
[PASS] import { Foo as Bar , Baz , } from 'module' ;
[PASS] import { Foo , Bar as Baz } from 'module' ;
[PASS] import { Foo , Bar as Baz , } from 'module' ;
[PASS] import { Foo as Bar , Baz as Qux } from 'module' ;
[PASS] import { Foo as Bar , Baz as Qux , } from 'module' ;
[PASS] import { Foo , Bar, Baz } from 'module' ;
[PASS] import { Foo , Bar, Baz , } from 'module' ;
[PASS] import { Foo as Bar , Baz , Qux } from 'module' ;
[PASS] import { Foo as Bar , Baz , Qux , } from 'module' ;
[PASS] import { Foo , Bar as Baz , Qux } from 'module' ;
[PASS] import { Foo , Bar as Baz , Qux , } from 'module' ;
[PASS] import { Foo , Bar , Baz as Qux } from 'module' ;
[PASS] import { Foo , Bar , Baz as Qux , } from 'module' ;
[PASS] import { Foo as Bar , Baz as Qux , Norf } from 'module' ;
[PASS] import { Foo as Bar , Baz as Qux , Norf , } from 'module' ;
[PASS] import { Foo as Bar , Baz , Qux as Norf } from 'module' ;
[PASS] import { Foo as Bar , Baz , Qux as Norf , } from 'module' ;
[PASS] import { Foo , Bar as Baz , Qux as Norf } from 'module' ;
[PASS] import { Foo , Bar as Baz , Qux as Norf , } from 'module' ;
[PASS] import { Foo as Bar , Baz as Qux , Norf as Enuf } from 'module' ;
[PASS] import { Foo as Bar , Baz as Qux , Norf as Enuf , } from 'module' ;
[PASS] import Default , * as All from 'module' ;
[PASS] import Default , { } from 'module' ;
[PASS] import Default , { Foo } from 'module' ;
[PASS] import Default , { Foo , } from 'module' ;
[PASS] import Default , { Foo as Bar } from 'module' ;
[PASS] import Default , { Foo as Bar , } from 'module' ;
[PASS] import Default , { Foo , Bar } from 'module' ;
[PASS] import Default , { Foo , Bar , } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz , } from 'module' ;
[PASS] import Default , { Foo , Bar as Baz } from 'module' ;
[PASS] import Default , { Foo , Bar as Baz , } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz as Qux } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz as Qux , } from 'module' ;
[PASS] import Default , { Foo , Bar, Baz } from 'module' ;
[PASS] import Default , { Foo , Bar, Baz , } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz , Qux } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz , Qux , } from 'module' ;
[PASS] import Default , { Foo , Bar as Baz , Qux } from 'module' ;
[PASS] import Default , { Foo , Bar as Baz , Qux , } from 'module' ;
[PASS] import Default , { Foo , Bar , Baz as Qux } from 'module' ;
[PASS] import Default , { Foo , Bar , Baz as Qux , } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz as Qux , Norf } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz as Qux , Norf , } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz , Qux as Norf } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz , Qux as Norf , } from 'module' ;
[PASS] import Default , { Foo , Bar as Baz , Qux as Norf } from 'module' ;
[PASS] import Default , { Foo , Bar as Baz , Qux as Norf , } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz as Qux , Norf as NoMore } from 'module' ;
[PASS] import Default , { Foo as Bar , Baz as Qux , Norf as NoMore , } from 'module' ;
[PASS] import "module" ;
[PASS] import Default from "module" ;
[PASS] import * as All from "module" ;
[PASS] import { } from "module" ;
[PASS] import { Foo } from "module" ;
[PASS] import { Foo , } from "module" ;
[PASS] import { Foo as Bar } from "module" ;
[PASS] import { Foo as Bar , } from "module" ;
[PASS] import { Foo , Bar } from "module" ;
[PASS] import { Foo , Bar , } from "module" ;
[PASS] import { Foo as Bar , Baz } from "module" ;
[PASS] import { Foo as Bar , Baz , } from "module" ;
[PASS] import { Foo , Bar as Baz } from "module" ;
[PASS] import { Foo , Bar as Baz , } from "module" ;
[PASS] import { Foo as Bar , Baz as Qux } from "module" ;
[PASS] import { Foo as Bar , Baz as Qux , } from "module" ;
[PASS] import { Foo , Bar, Baz } from "module" ;
[PASS] import { Foo , Bar, Baz , } from "module" ;
[PASS] import { Foo as Bar , Baz , Qux } from "module" ;
[PASS] import { Foo as Bar , Baz , Qux , } from "module" ;
[PASS] import { Foo , Bar as Baz , Qux } from "module" ;
[PASS] import { Foo , Bar as Baz , Qux , } from "module" ;
[PASS] import { Foo , Bar , Baz as Qux } from "module" ;
[PASS] import { Foo , Bar , Baz as Qux , } from "module" ;
[PASS] import { Foo as Bar , Baz as Qux , Norf } from "module" ;
[PASS] import { Foo as Bar , Baz as Qux , Norf , } from "module" ;
[PASS] import { Foo as Bar , Baz , Qux as Norf } from "module" ;
[PASS] import { Foo as Bar , Baz , Qux as Norf , } from "module" ;
[PASS] import { Foo , Bar as Baz , Qux as Norf } from "module" ;
[PASS] import { Foo , Bar as Baz , Qux as Norf , } from "module" ;
[PASS] import { Foo as Bar , Baz as Qux , Norf as NoMore } from "module" ;
[PASS] import { Foo as Bar , Baz as Qux , Norf as NoMore , } from "module" ;
[PASS] import Default , * as All from "module" ;
[PASS] import Default , { } from "module" ;
[PASS] import Default , { Foo } from "module" ;
[PASS] import Default , { Foo , } from "module" ;
[PASS] import Default , { Foo as Bar } from "module" ;
[PASS] import Default , { Foo as Bar , } from "module" ;
[PASS] import Default , { Foo , Bar } from "module" ;
[PASS] import Default , { Foo , Bar , } from "module" ;
[PASS] import Default , { Foo as Bar , Baz } from "module" ;
[PASS] import Default , { Foo as Bar , Baz , } from "module" ;
[PASS] import Default , { Foo , Bar as Baz } from "module" ;
[PASS] import Default , { Foo , Bar as Baz , } from "module" ;
[PASS] import Default , { Foo as Bar , Baz as Qux } from "module" ;
[PASS] import Default , { Foo as Bar , Baz as Qux , } from "module" ;
[PASS] import Default , { Foo , Bar, Baz } from "module" ;
[PASS] import Default , { Foo , Bar, Baz , } from "module" ;
[PASS] import Default , { Foo as Bar , Baz , Qux } from "module" ;
[PASS] import Default , { Foo as Bar , Baz , Qux , } from "module" ;
[PASS] import Default , { Foo , Bar as Baz , Qux } from "module" ;
[PASS] import Default , { Foo , Bar as Baz , Qux , } from "module" ;
[PASS] import Default , { Foo , Bar , Baz as Qux } from "module" ;
[PASS] import Default , { Foo , Bar , Baz as Qux , } from "module" ;
[PASS] import Default , { Foo as Bar , Baz as Qux , Norf } from "module" ;
[PASS] import Default , { Foo as Bar , Baz as Qux , Norf , } from "module" ;
[PASS] import Default , { Foo as Bar , Baz , Qux as Norf } from "module" ;
[PASS] import Default , { Foo as Bar , Baz , Qux as Norf , } from "module" ;
[PASS] import Default , { Foo , Bar as Baz , Qux as Norf } from "module" ;
[PASS] import Default , { Foo , Bar as Baz , Qux as Norf , } from "module" ;
[PASS] import Default , { Foo as Bar , Baz as Qux , Norf as Enuf } from "module" ;
[PASS] import Default , { Foo as Bar , Baz as Qux , Norf as Enuf , } from "module" ;

Good job @pilwon, but two points/questions

1. What about multilines import statement?
2. What about adding some negative test, because I found out that following regexs are considered as valid, which is wrong:

import "fo o"
import foo from from "foo"
import import foo from "foo"
import foo import foo from "foo

@pilwon great extraction from React :) 👍 For most cases will work and will help for some parser :)

@stefanbuck, it's normal :D RegExps can't handle everything. Pretty enough for me to build a parser :)

the quote regex is brittle, something like this should be used instead:

const ES6_IMPORT_REGEX = /\bimport\s+(?:.+\s+from\s+)?(['"])([^\1]+)(\1)/g;