babel-plugin-decorator-metadata-typescript v0.1.1

babel-decorators-metadata

This is an experimental babel plugin that emits decorator metadata. Based on requirements from here

Limitations:

• If no type annotation is present we have no type to write
• If we have a type reference, we can only use the type name, we can't check if the refence is to an interface, as type alias, a class or an enum. In practice this means that :
  • If the type is an interface or a type alias, the type name will be undefined at runtime, to avoid the undefined we can do type || Object to default to object if the type does not have a runtime value associated
  • If the type is an enum, Typescript would write Number or String in the metadata, depending on the type of the enum. Since we write the type name to the metadata, this means you will end up with the container object of the enum inside the metadata.

Usage

Install

npm install babel-plugin-decorator-metadata-typescript

Sample .babelrc

{
  "env": {},
  "ignore": [],
  "plugins": [
    "decorator-metadata-typescript",
    ["@babel/plugin-proposal-decorators", { "legacy": true }],
    ["@babel/plugin-proposal-class-properties", { "loose": true }],
    "babel-plugin-transform-es2015-modules-commonjs"
  ],
  "presets": [
    "@babel/preset-typescript"
  ]
}