Are the types wrong?

Special thanks to @userquin for his help and his PR inspired me to write this article.

Concise and to the point. If there are any inaccuracies, please correct me. Also, refer to the official documentation arethetypeswrong

What is `arethetypeswrong`?

arethetypeswrong (abbreviated as attw below) is a tool for analyzing TypeScript types of npm packages. By analyzing the type definition files of npm packages, attw finds problems in them and provides suggestions for fixing them. The goal of attw is to help developers better understand the type definitions of npm packages and improve code quality.

It can help you analyze and detect the following problems:

How to use `arethetypeswrong`?

You can use it online at https://arethetypeswrong.github.io/ or use the CLI tool in your project.

pnpm i -D @arethetypeswrong/cli

使用 attw --pack 检查单个包，在您的scripts中添加：

Use attw --pack to check a single package, add it to your scripts:

{
  "scripts": {
    "attw": "attw --pack"
  }
}

Or without installing, use npx directly:

npx --yes @arethetypeswrong/cli

Check packages from npm:

npx --yes @arethetypeswrong/cli --from-npm @arethetypeswrong/cli

Configuration

attw supports a JSON config file (by default named .attw.json) which allows you to pre-set the command line arguments. The options are a one-to-one mapping of the command line flags, changed to camelCase, and are all documented in their relevant Options section below.

Options

Help

Show help information and exit.

In the CLI: --help, -h

attw --help

Version

Print the current version of attw and exit.

In the CLI: --version, -v

attw --version

Pack

Specify a directory to run npm pack in (instead of specifying a tarball filename), analyze the resulting tarball, and delete it afterwards.

attw --pack .

From NPM

Specify the name (and, optionally, version or SemVer range) of a package from the NPM registry instead of a local tarball filename.

In the CLI: --from-npm, -p

attw --from-npm <package-name>

In the config file, fromNpm can be a boolean value.

DefinitelyTyped

When a package does not contain types, specifies the version or SemVer range of the DefinitelyTyped @types package to use. Defaults to inferring the best version match from the implementation package version.

In the CLI: --definitely-typed, --no-definitely-typed

attw -p <package-name> --definitely-typed <version>
attw -p <package-name> --no-definitely-typed

Format

The format to print the output in. Defaults to auto.

The available values are:

table, where columns are entrypoints and rows are resolution kinds
table-flipped, where columns are resolution kinds and rows are entrypoints
ascii, for large tables where the output is clunky
auto, which picks whichever of the above best fits the terminal width
json outputs the raw JSON data (overriding all other rendering options)

In the CLI: --format, -f

attw --format <format> <file-name>

In the config file, format can be a string value.

Entrypoints

attw automatically discovers package entrypoints by looking at package.json exports and subdirectories with additional package.json files. In a package lacking exports, providing the --entrypoints-legacy option will include all published code files. This automatic discovery process can be overridden with the --entrypoints option, or altered with the --include-entrypoints and --exclude-entrypoints options:

attw --pack . --entrypoints . one two three    # Just ".", "./one", "./two", "./three"
attw --pack . --include-entrypoints added      # Auto-discovered entrypoints plus "./added"
attw --pack . --exclude-entrypoints styles.css # Auto-discovered entrypoints except "./styles.css"
attw --pack . --entrypoints-legacy             # All published code files

Profiles

Profiles select a set of resolution modes to require/ignore. All are evaluated but failures outside of those required are ignored.

The available profiles are:

strict - requires all resolutions
node16 - ignores node10 resolution failures
esm-only - ignores CJS resolution failures

In the CLI: --profile

attw <file-name> --profile <profile>

In the config file, profile can be a string value.

Ignore Rules

Specifies rules/problems to ignore (i.e. not raise an error for).

The available values are:

no-resolution
untyped-resolution
false-cjs
false-esm
cjs-resolves-to-esm
fallback-condition
cjs-only-exports-default
false-export-default
unexpected-module-syntax
missing-export-equals
internal-resolution-error
named-exports

In the CLI: --ignore-rules

attw <file-name> --ignore-rules <rules...>

In the config file, ignoreRules can be an array of strings. For example, to ignore no-resolution and untyped-resolution in config file:

{
  "ignoreRules": ["no-resolution", "untyped-resolution"]
}

Summary/No Summary

Whether to display a summary of what the different errors/problems mean. Defaults to showing the summary (--summary).

In the CLI: --summary/--no-summary

attw --summary/--no-summary <file-name>

In the config file, summary can be a boolean value.

Emoji/No Emoji

Whether to print the information with emojis. Defaults to printing with emojis (--emoji).

In the CLI: --emoji/--no-emoji

attw --emoji/--no-emoji <file-name>

In the config file, emoji can be a boolean value.

Color/No Color

Whether to print with colors. Defaults to printing with colors (--color).

The FORCE_COLOR env variable is also available for use (set is to 0 or 1).

In the CLI: --color/--no-color

attw --color/--no-color <file-name>

In the config file, color can be a boolean value.

Quiet

When set, nothing will be printed to STDOUT.

In the CLI: --quiet, -q

attw --quiet <file-name>

In the config file, quiet can be a boolean value.

Config Path

The path to the config file. Defaults to ./.attw.json.

In the CLI: --config-path <path>

attw --config-path <path> <file-name>

Cannot be set from within the config file itself.

What is arethetypeswrong?

How to use arethetypeswrong?