| # reserved-identifiers |
| |
| > Provides a list of [reserved identifiers](https://262.ecma-international.org/14.0/#sec-keywords-and-reserved-words) for JavaScript |
| |
| It assumes the latest JavaScript version (ES2023) and module context. Supporting older JavaScript versions is a non-goal. |
| |
| ## Install |
| |
| ```sh |
| npm install reserved-identifiers |
| ``` |
| |
| ## Usage |
| |
| ```js |
| import reservedIdentifiers from 'reserved-identifiers'; |
| |
| const identifiers = reservedIdentifiers(); |
| const isReserved = identifier => identifiers.has(identifier); |
| |
| console.log(isReserved('await')); |
| //=> true |
| ``` |
| |
| ## API |
| |
| ### reservedIdentifiers(options?) |
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| Returns a `Set` with the identifiers. |
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| #### options |
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| Type: `object` |
| |
| ##### includeGlobalProperties |
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| Type: `boolean`\ |
| Default: `false` |
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| Include the [global properties](https://tc39.es/ecma262/#sec-value-properties-of-the-global-object) `globalThis`, `Infinity`, `NaN`, and `undefined`. Although not officially reserved, they should typically [not be used as identifiers](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined#sect1). |
| |
| ### typeScriptReservedTypes() |
| |
| Returns a `Set` with TypeScript's built-in types that are reserved and cannot be used for type names (interfaces, type aliases, enums, classes, type parameters). |
| |
| ```js |
| import {typeScriptReservedTypes} from 'reserved-identifiers'; |
| |
| const types = typeScriptReservedTypes(); |
| |
| console.log(types.has('any')); |
| //=> true |
| |
| console.log(types.has('unknown')); |
| //=> true |
| ``` |
| |
| ## Related |
| |
| - [is-identifier](https://github.com/sindresorhus/is-identifier) - Check if a string is a valid JavaScript identifier |
