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  • License MIT

Transform TypeScript `const` enums

Package Exports

  • babel-plugin-const-enum

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (babel-plugin-const-enum) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

babel-plugin-const-enum

Transform TypeScript const enums

Install

Using npm:

npm install --save-dev babel-plugin-const-enum

or using yarn:

yarn add babel-plugin-const-enum --dev

Usage

removeConst (default)

Removes the const keyword to use regular enum. Can be used in a slower dev build to allow const, while prod still uses tsc. See babel#6476.

// Before:
const enum MyEnum {
  A = 1,
  B = A,
  C,
  D = C,
  E = 1,
  F,
  G = A * E,
  H = A ** B ** C,
  I = A << 20
}

// After:
enum MyEnum {
  A = 1,
  B = A,
  C,
  D = C,
  E = 1,
  F,
  G = A * E,
  H = A ** B ** C,
  I = A << 20
}

.babelrc

{
  "plugins": [
    "const-enum"
  ]
}

Or Explicitly:

.babelrc

{
  "plugins": [
    [
      "const-enum",
      {
        "transform": "removeConst"
      }
    ]
  ]
}

constObject

Transforms into a const object literal. Can be further compressed using Uglify/Terser to inline enum access. See babel#8741.

// Before:
const enum MyEnum {
  A = 1,
  B = A,
  C,
  D = C,
  E = 1,
  F,
  G = A * E,
  H = A ** B ** C,
  I = A << 20
}

// After:
const MyEnum = {
  A: 1,
  B: 1,
  C: 2,
  D: 2,
  E: 1,
  F: 2,
  G: 1,
  H: 1,
  I: 1048576
};

.babelrc

{
  "plugins": [
    [
      "const-enum",
      {
        "transform": "constObject"
      }
    ]
  ]
}