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a sample code of how to use const as const instead of enums in TypeScript
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| /* | |
| from: | |
| Enums considered harmful | Matt Pocock | |
| https://www.youtube.com/watch?v=jjMbPt_H3RQ | |
| */ | |
| const LogLevel = { | |
| DEBUG: "DEBUG", | |
| INFO: "INFO", | |
| WARNING: "WARNING", | |
| ERROR: "ERROR" | |
| } as const; | |
| type TLogLevelKeys = keyof typeof LogLevel; | |
| type TLogLevel = typeof LogLevel[TLogLevelKeys]; | |
| const log = (message: string, level: TLogLevel = LogLevel.DEBUG) => console.log(`${LogLevel[level]}: ${message}`); | |
| log("DEBUG value from const", LogLevel.DEBUG); | |
| //---------------------------------------------// | |
| enum ELogLevel { | |
| DEBUG = "DEBUG", | |
| INFO = "INFO", | |
| WARNING = "WARNING", | |
| ERROR = "ERROR" | |
| } | |
| console.log("DEBUG value from enum", ELogLevel.DEBUG); |
Author
Author
Sandro Maglione on X: "Typescript wizardy: as const + satisfies Combine both to have type safety on Record keys and values + constant inferred types You can then extract both keys and values as unions using keyof and typeof 🧙 https://t.co/cUH05nNXl2" / X
Author
Sandro Maglione on X: "satisfies makes everything type safe in typescript Combine it with union types and template literals to stop worrying about typos ever again 🥳 https://t.co/n2FBALhlzv" / X
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code at the typescript playground
JavaScript output:
Other useful references:
Enums | TypeScript Docs
Using TypeScript Enums as Const: A Complete Guide
Combining TypeScript satisfies operator and const assertion | Chris Vaillancourt
Enums | Total TypeScript
5 Ways to Use 'Satisfies' in TypeScript | Total TypeScript