javascript-identifier-regex) in Node.js (original) (raw)

// Note: run `npm install` first!

'use strict';

const fs = require('fs');

const regenerate = require('regenerate');

const template = require('lodash.template');

// Which Unicode version should be used?

const version = '11.0.0';

// Set up a shorthand function to import Unicode data.

const get = function(what) {

return require(`unicode-${ version }/${ what }/code-points.js`);

};

// Get the Unicode categories needed to construct the ES5 regex.

const Lu = get('General_Category/Uppercase_Letter');

const Ll = get('General_Category/Lowercase_Letter');

const Lt = get('General_Category/Titlecase_Letter');

const Lm = get('General_Category/Modifier_Letter');

const Lo = get('General_Category/Other_Letter');

const Nl = get('General_Category/Letter_Number');

const Mn = get('General_Category/Nonspacing_Mark');

const Mc = get('General_Category/Spacing_Mark');

const Nd = get('General_Category/Decimal_Number');

const Pc = get('General_Category/Connector_Punctuation');

// Get the Unicode properties needed to construct the ES6 regex.

const ID_Start = get('Binary_Property/ID_Start');

const ID_Continue = get('Binary_Property/ID_Continue');

const Other_ID_Start = get('Binary_Property/Other_ID_Start');

const compileRegex = template('/^(?!(?:<%= reservedWords %>)$)' +

'(?:<%= identifierStart %>)(?:<%= identifierPart %>)*$/');

const generateES5Regex = function() { // ES 5.1

// https://mathiasbynens.be/notes/javascript-identifiers#valid-identifier-names

const identifierStart = regenerate('$', '_')

.add(Lu, Ll, Lt, Lm, Lo, Nl)

.removeRange(0x010000, 0x10FFFF); // Remove astral symbols.

const identifierPart = identifierStart.clone()

.add('\u200C', '\u200D', Mn, Mc, Nd, Pc)

.removeRange(0x010000, 0x10FFFF); // Remove astral symbols.

const reservedWords = [

// https://mathiasbynens.be/notes/reserved-keywords#ecmascript-5

'do', 'if', 'in', 'for', 'let', 'new', 'try', 'var', 'case', 'else',

'enum', 'eval', 'null', 'this', 'true', 'void', 'with', 'break', 'catch',

'class', 'const', 'false', 'super', 'throw', 'while', 'yield', 'delete',

'export', 'import', 'public', 'return', 'static', 'switch', 'typeof',

'default', 'extends', 'finally', 'package', 'private', 'continue',

'debugger', 'function', 'arguments', 'interface', 'protected',

'implements', 'instanceof',

// These aren’t strictly reserved words, but they kind of behave as if

// they were.

//'NaN', 'Infinity', 'undefined'

];

const regex = compileRegex({

'reservedWords': reservedWords.join('|'),

'identifierStart': identifierStart.toString(),

'identifierPart': identifierPart.toString()

});

return regex;

};

const generateES6Regex = function() {

// http://ecma-international.org/ecma-262/6.0/#sec-identifier-names-static-semantics-early-errors

// http://unicode.org/reports/tr31/#Default\_Identifier\_Syntax

// https://bugs.ecmascript.org/show\_bug.cgi?id=2717#c0

const identifierStart = regenerate(ID_Start)

// Note: this already includes `Other_ID_Start`. http://git.io/wRCAfQ

.add(

'$',

'_'

);

const identifierPart = regenerate(ID_Continue)

// Note: `ID_Continue` already includes `Other_ID_Continue`. http://git.io/wRCAfQ

.add(Other_ID_Start)

.add(

'$',

'_',

'\u200C',

'\u200D'

);

const reservedWords = [

// https://mathiasbynens.be/notes/reserved-keywords#ecmascript-6

'do', 'if', 'in', 'for', 'let', 'new', 'try', 'var', 'case', 'else',

'enum', 'eval', 'null', 'this', 'true', 'void', 'with', 'await', 'break',

'catch', 'class', 'const', 'false', 'super', 'throw', 'while', 'yield',

'delete', 'export', 'import', 'public', 'return', 'static', 'switch',

'typeof', 'default', 'extends', 'finally', 'package', 'private',

'continue', 'debugger', 'function', 'arguments', 'interface', 'protected',

'implements', 'instanceof',

// These aren’t strictly reserved words, but they kind of behave as if

// they were.

//'NaN', 'Infinity', 'undefined'

];

const regex = compileRegex({

'reservedWords': reservedWords.join('|'),

'identifierStart': identifierStart.toString(),

'identifierPart': identifierPart.toString()

});

return regex;

};

fs.writeFileSync(

'ecmascript-5.1.js',

`// ECMAScript 5.1:\n\n${ generateES5Regex() }\n`

);

fs.writeFileSync(

'ecmascript-6.js',

`// ECMAScript 6:\n\n${ generateES6Regex() }\n`

);