type-coverage

type-coverage

A CLI tool to check type coverage for typescript code

This tool will check type of all identifiers, the type coverage rate = the count of identifiers whose type is not any / the total count of identifiers, the higher, the better.

install

yarn global add type-coverage

usage

run type-coverage

arguments

name	type	description
-p, --project	string?	tell the CLI where is the tsconfig.json
--detail	boolean?	show detail
--at-least	number?	fail if coverage rate < this value
--debug	boolean?	show debug info
--strict	boolean?	strict mode
--ignore-catch	boolean?	ignore catch
--cache	boolean?	enable cache

strict mode

If the identifiers' type arguments exist and contain at least one any, like any[], ReadonlyArray<any>, Promise<any>, Foo<number, any>, it will be considered as any too

Also, future minor release may introduce stricter type check in this mode, which may lower the type coverage rate

enable cache

save and reuse type check result of files that is unchanged and independent of changed files in .type-coverage directory, to improve speed

ignore catch

If you want to get 100% type coverage then try {} catch {} is the largest blocked towards that.

This can be fixed in typescript with Allow type annotation on catch clause variable but until then you can turn on --ignore-catch --at-least 100.

Your catch blocks should look like

try {
  await ...
} catch (anyErr) {
  const err = <Error> anyErr
}

To have the highest type coverage.

config in package.json

  "typeCoverage": {
    "atLeast": 99 // same as --at-least
  },

ingore line

Use type-coverage:ignore-next-line or type-coverage:ignore-line in comment(// or /* */) to ignore any in a line.

try {
  // type-coverage:ignore-next-line
} catch (error) { // type-coverage:ignore-line
}

vscode plugin

https://marketplace.visualstudio.com/items?itemName=york-yao.vscode-type-coverage

add dynamic badges of type coverage rate

Use your own project url:

[![type-coverage](https://img.shields.io/badge/dynamic/json.svg?label=type-coverage&prefix=%E2%89%A5&suffix=%&query=$.typeCoverage.atLeast&uri=https%3A%2F%2Fraw.githubusercontent.com%2Fplantain-00%2Ftype-coverage%2Fmaster%2Fpackage.json)](https://github.com/plantain-00/type-coverage)

API

export function lint(
  project: string,
  detail: boolean,
  debug: boolean,
  files?: string[],
  oldProgram?: ts.Program,
  strict = false,
  enableCache = false,
  ignoreCatch = false
): Promise<{
  correctCount: number
  totalCount: number
  anys: {
    file: string
    line: number
    character: number
    text: string
  }[]
  program: ts.Program
}>

FAQ

Q: Does this count JavaScript files?

Yes, This package calls Typescript API, Typescript can parse Javascript file(with allowJs), then this package can too.

Changelog

1.13.0 (2019-04-17)

• feat: change --ignoreCatch to --ignore-cache (8aded79)
• feat: add --ignore-catch functionality (2620a65)
• chore: update dependencies (1036002) (d335801) (bfd7cd5)