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TypeScript better enums
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// | |
// Thanks to Matt Pocock's video "Enums considered harmful" | |
// https://www.youtube.com/watch?v=jjMbPt_H3RQ | |
// | |
// Please note that enums per se are great in any language, | |
// but TypeScript's enums are implemented in a convoluted and verbose way (as of version 4.9) | |
// since JavaScript (as of ES2022) does not natively support enums | |
// | |
// This can be moved elsewhere | |
type EnumLike<T> = T[keyof T]; | |
// "as const" turns this into a readonly, "real" constant | |
const LOG_LEVEL = { | |
DEBUG: 'DEBUG', | |
WARNING: 'WARNING', | |
ERROR: 'ERROR', | |
} as const; | |
// This is the associated type of the readonly constant | |
// In case you want to use it as a type | |
type LogLevel = EnumLike<typeof LOG_LEVEL> | |
// Example function using the LogLevel associated type | |
function logMe(level: LogLevel, message: string): void { | |
// ... | |
} | |
// Example usage of the example function | |
logMe('DEBUG', 'It works with literals'); | |
logMe(LOG_LEVEL.DEBUG, 'As well as enum-like access'); |
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