Convert object values to enum-like type in TypeScript

Question

The type of ParsedParametersObject["--mode"] must be one of Parameters[ValidFirstCommandPhrases.buildProject].mode.values. Currently it has been hardcoded, so when new supported mode will be added to application we need to edit both Parameters[ValidFirstCommandPhrases.buildProject].mode.values and ParsedParametersObject.

How I can convert Parameters[ValidFirstCommandPhrases.buildProject].mode.values to valid enum-like type?

enum ValidFirstCommandPhrases {
 initializeProject = "initializeProject",
 buildProject = "buildProject"
}

export const Parameters = {
    [ValidFirstCommandPhrases.buildProject]: {
      mode: {
        name__includingDoubleNDash: "--mode",
        values: {
          development: "development",
          production: "production",
        }
      },
      debug: {
       name__includingDoubleNDash: "--debug"
     }
  }
} as const;

type ParsedParametersObject = {
    // --mode
  [Parameters[ValidFirstCommandPhrases.buildProject].mode.name__includingDoubleNDash]:
    "development" | "production"; // Hardcoded!!
}

nicolasrigaudiere · Accepted Answer · 2020-04-07 15:40:26Z

1

An option you can use is to have a dedicated ENVIRONMENTS enum and use it as a type in ParsedParametersObject["--mode"]'s type.

See below

enum ValidFirstCommandPhrases {
 initializeProject = "initializeProject",
 buildProject = "buildProject"
}

enum ENVIRONMENTS {
    DEVELOPMENT = 'development',
    PRODUCTION = 'production'
}

export const Parameters = {
    [ValidFirstCommandPhrases.buildProject]: {
      mode: {
        name__includingDoubleNDash: "--mode",
        values: {
          development: ENVIRONMENTS.DEVELOPMENT,
          production: ENVIRONMENTS.PRODUCTION,
        }
      },
      debug: {
       name__includingDoubleNDash: "--debug"
     }
  }
} as const;

type ParsedParametersObject = {
    // --mode
  [Parameters[ValidFirstCommandPhrases.buildProject].mode.name__includingDoubleNDash]: 
ENVIRONMENTS;
}

Hope it helps!

answered Apr 7, 2020 at 15:40

nicolasrigaudiere

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1 Comment

Takeshi Tokugawa YD Over a year ago

It will! Thank you for the answer!

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