ts-unused-exports

ts-unused-exports finds unused exported symbols in your Typescript project.

Installation

npm install --save-dev ts-unused-exports

or, to install globally:

npm install -g ts-unused-exports

Usage

./node_modules/.bin/ts-unused-exports path/to/tsconfig.json [file1.ts ...] [options]

or, if installed globally:

ts-unused-exports path/to/tsconfig.json [file1.ts ...] [options]

or, as a library:

import analyzeTsConfig from 'ts-unused-exports';
const result = analyzeTsConfig('path/to/tsconfig.json');
// or const result = analyzeTsConfig('path/to/tsconfig.json', ['file1.ts']);
// or const result = analyzeTsConfig('path/to/tsconfig.json', ['file1.ts', '--excludePathsFromReport=math']);

// result : { [index:string] : ExportNameAndLocation[] }
// where the keys are file paths and the values are a structure descibing unused symbols:
// interface ExportNameAndLocation {
//   exportName: string;
//   location: LocationInFile;
// }

Options:

Option name	Description	Example
`allowUnusedEnums`	Allow unused `enum`s.	`--allowUnusedEnums`
`allowUnusedTypes`	Allow unused `type` or `interface`.	`--allowUnusedTypes`
`excludeDeclarationFiles`	Exclude `.d.ts` files when looking for unused exports.	`--excludeDeclarationFiles`
`maxIssues`	Return successfully for up to a given number of modules with unused exports.	`--maxIssues=7`
`exitWithCount`	Set the process exit code to be the count of files that have unused exports.	`--exitWithCount`
`exitWithUnusedTypesCount`	Set the process exit code to be the total count of unused exported types.	`--exitWithUnusedTypesCount`
`ignoreFiles`	Ignore files with filenames that match the given regex. Use this to exclude groups of files - for example test files and their utilities.	`--ignoreFiles=.*spec`
`ignoreProductionFiles`	Only scan test files (so ignore non-test 'production' files).	`--ignoreProductionFiles`
`ignoreTestFiles`	Only scan production files (ignore all test files, like `spec.ts(x)` or `test.ts(x)` or `TestUtils.ts`). Use this to detect production code that is only used in tests (so is dead code). Note: this will NOT detect unused exports in test code - for that, you can run `ts-unused-exports` separately with the `--ignoreProductionFiles` option.	`--ignoreTestFiles`
`excludePathsFromReport`	Exclude files from the output that match the given path segments.	`--excludePathsFromReport=math;utils`
`searchNamespaces`	Enable searching for unused exports within namespaces. Note: this can affect performance on large codebases.	`--searchNamespaces`
`showLineNumber`	Show the line number and column of the unused export.	`--showLineNumber`
`silent`	Don't write on stdout on success.	`--silent`

Note that if ts-unused-exports is called without files, the files will be read from the tsconfig's files or include key which must be present. If called with files, then those file paths should be relative to the tsconfig.json, just like you would specify them in your tsconfig's files key.

ts-unused-exports also resolves path aliases specified in tsconfig's paths object.

As of version 7.0.0 the TypeScript compiler is a peer dependency of ts-unused-exports. This means that if the TypeScript compiler is not already in the same spot as ts-unused-exports, you have to install it yourself (e.g. with npm i -D typescript).

Why should I use this?

If you've ever used tslint's no-unused-variable rule you already known how awesome it is. What this rule does is detect code in your modules that is not being used so that you can remove it.

For example, say that you refactored your math.ts module so that you no longer use add1:

function add1(x: number) {
  return x + 1;
} // warning here

export default (x: number) => x + 1;

When run, tslint will complain that add1 is no longer in use.

Unfortunately, if your symbols are exported, tslint does not complain anymore. Effectively exporting a symbol anchors the symbol so that, even if nobody uses it, it will not be marked as dead code.

If you've ever found yourself mid-refactor fixing a particularly fiendish function only to realize later that nobody really uses it you know exactly what I mean.

ts-unused-exports fills this cross-module gap by complaining about exported symbols that no-one cares about.

In this sense, ts-unused-exports does not replace tslint but rather complements it by helping you detect unnecessary exports. Once those are fixed, tslint's no-unused-variable rule will kick in and tell you which code you can safely remove.

Example

There is a (very silly) example in the example/simple directory.

If you want to run it you can:

git clone https://github.com/pzavolinsky/ts-unused-exports
cd ts-unused-exports
./bin/ts-unused-exports example/simple/tsconfig.json
# or: node ./bin/ts-unused-exports example/simple/tsconfig.json
# or: node bin\ts-unused-exports example\simple\tsconfig.json

The output should be:

2 modules with unused exports
/home/stuff/src/github/ts-unused-exports/example/simple/math.ts: add1
/home/stuff/src/github/ts-unused-exports/example/simple/unused.ts: unused

Exit Code

Normally, the exit code follows the convention used by eslint:

0 = Linting was successful and there are no linting errors.
1 = Linting was successful and there is at least one linting error.
2 = Linting was unsuccessful due to bad arguments or an internal error.

If the option --maxIssues=n is used, then linting is considered successful, if at most n issues are found.

If the option --exitWithCount is used, then the exit status will equal the number of offending modules:

echo $?
# or: echo %ERRORLEVEL%
2

Similarly, the option --exitWithUnusedTypesCount means that the exit status will equal the number of offending types.

Specifying which TypeScript files to check

If not using files or include inside your tsconfig (e.g. using webpack with ts-loader), you can explicitly specify the files to check in the command line:

./bin/ts-unused-exports example/simple/tsconfig.json app.ts math.ts

or, in a more generic way:

./bin/ts-unused-exports example/simple/tsconfig.json $(cd example/simple; find -name '*.ts')

You can use comment flags to ignore exports:

// ts-unused-exports:disable-next-line
export function add2(x: number) {
  return x + 2;
}

Tools

Here are some tools that can be used with ts-unused-exports. note: these tools are separate, external projects, and we are not the maintainers. So, if you have feedback or issues with these tools, please first check in with the tool authors.

Tool	Description
eslint plugin	An eslint plugin that executes `ts-unused-exports` over your code.

Changelog (Release History)

To see what has changed in each version, please see our CHANGELOG.md.

Contributing

ts-unused-exports is maintained by volunteers, working in their free time. If you'd like to help out, please see CONTRIBUTING.md.

ts-unused-exports was created by Patricio Zavolinsky. Improvements were contributed by the open source community.

Licence: MIT

This project is licensed under the MIT License - see the LICENSE file for details

wongjiahau/ts-unused-exports