@polymer/gen-typescript-declarations

gen-typescript-declarations

A library which generates TypeScript declarations for Polymer and custom elements.

How do I use the typings?

Polymer

Typings for Polymer 2 are planned for regular release starting with version 2.4, and are available in the types/ directory on the master branch now.

Once Polymer 2.4 is released, to use the typings, install Polymer normally from Bower, and add a triple-slash directive anywhere in your TypeScript project for the typings you require. Each HTML import from Polymer has a corresponding typings file. For example, if you depend on polymer-element.html:

/// <reference path="./bower_components/polymer/types/polymer-element.d.ts" />`

class MyElement extends Polymer.Element {
  ...
}

Alternatively, you can add the dependency to tsconfig.json in the root of your project:

{
...
	"include": [
		"src/**/*.ts",
		"src/bower_components/polymer/**/*.d.ts",
	]
}

Typings for Polymer 3 are planned but not yet available (see #18).

You may also be interested in the Polymer decorators.

How do I generate new typings?

You can run this package from the command line with gen-tsd, or as a library with the generateDeclarations function.

It is recommended to integrate typings generation as part of your build/release process:

$ npm install --save-dev @polymer/gen-typescript-declarations

Add a gen-tsd script to your package.json:

{
  ...
  "scripts": {
    "gen-tsd": "gen-tsd"
  }
}

If you're using Bower, ensure you run npm run gen-tsd to generate the latest typings and commit them to your repository before tagging each release.

If you're using NPM, you can instead add this script to the NPM prepack script to generate and include typings in your NPM package every time you publish.

Config options

By default the gen-tsd command will read a file called gen-tsd.json in your root directory. It has the following options:

• excludeFiles: string[]

  Skip source files whose paths match any of these glob patterns. If undefined, defaults to excluding directories ending in "test" or "demo".

• excludeIdentifiers: string[]

  Do not emit any declarations for features that have any of these identifiers.

• removeReferences: string[]

  Remove any triple-slash references to these files, specified as paths relative to the analysis root directory.

• addReferences: {[filepath: string]: string[]}

  Additional files to insert as triple-slash reference statements. Given the map a: b[], a will get an additional reference statement for each file path in b. All paths are relative to the analysis root directory.

• renameTypes: {[name: string]: string}

  Whenever a type with a name in this map is encountered, replace it with the given name. Note this only applies to named types found in places like function/method parameters and return types. It does not currently rename e.g. entire generated classes.

Using as a module

You can also use this package as a module:

import {generateDeclarations} from 'gen-typescript-declarations';

const config = {
  "exclude": [
    "test/**",
  ],
  "removeReferences": [
    "../shadycss/apply-shim.d.ts",
  ],
  "addReferences": {
    "lib/utils/boot.d.ts": [
      "extra-types.d.ts"
    ]
  },
  "renameTypes": {
    "Polymer_PropertyEffects": "Polymer.PropertyEffects"
  }
}

// A map of d.ts file paths to file contents.
const declarations = await generateDeclarations('/my/root/dir', config);

FAQ

Why are some typings missing?

This library is based on Polymer Analyzer which has limitations in its static analysis. For certain patterns, Analyzer relies on additional JSDoc annotations.

Can I augment the generated typings with hand-written ones?

Yes, see the addReferences config option above.