82 lines
1.8 KiB
JavaScript
82 lines
1.8 KiB
JavaScript
import {IS_IDENTIFIER_CHAR, IS_IDENTIFIER_START} from "../parser/util/identifier";
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// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar
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// Hard-code a list of reserved words rather than trying to use keywords or contextual keywords
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// from the parser, since currently there are various exceptions, like `package` being reserved
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// but unused and various contextual keywords being reserved. Note that we assume that all code
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// compiled by Sucrase is in a module, so strict mode words and await are all considered reserved
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// here.
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const RESERVED_WORDS = new Set([
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// Reserved keywords as of ECMAScript 2015
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"break",
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"case",
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"catch",
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"class",
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"const",
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"continue",
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"debugger",
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"default",
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"delete",
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"do",
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"else",
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"export",
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"extends",
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"finally",
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"for",
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"function",
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"if",
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"import",
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"in",
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"instanceof",
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"new",
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"return",
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"super",
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"switch",
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"this",
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"throw",
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"try",
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"typeof",
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"var",
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"void",
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"while",
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"with",
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"yield",
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// Future reserved keywords
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"enum",
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"implements",
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"interface",
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"let",
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"package",
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"private",
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"protected",
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"public",
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"static",
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"await",
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// Literals that cannot be used as identifiers
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"false",
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"null",
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"true",
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]);
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/**
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* Determine if the given name is a legal variable name.
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*
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* This is needed when transforming TypeScript enums; if an enum key is a valid
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* variable name, it might be referenced later in the enum, so we need to
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* declare a variable.
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*/
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export default function isIdentifier(name) {
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if (name.length === 0) {
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return false;
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}
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if (!IS_IDENTIFIER_START[name.charCodeAt(0)]) {
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return false;
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}
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for (let i = 1; i < name.length; i++) {
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if (!IS_IDENTIFIER_CHAR[name.charCodeAt(i)]) {
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return false;
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}
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}
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return !RESERVED_WORDS.has(name);
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}
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