infctr / ts-unused-exports

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

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 ...]

or, if installed globally:

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

or:

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

// result : { [index:string] : string[] }
// where the keys are file paths and the values are unused symbols

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 specifie them in your tsconfig's files key.

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

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/ 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/tsconfig.json
# or: node ./bin/ts-unused-exports example/tsconfig.json
# or: node bin\ts-unused-exports example\tsconfig.json

The output should be:

1 module with unused exports
math: add1

Also note the exit status (which equals the number of offending modules):

echo $?
# or: echo %ERRORLEVEL%
1

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/tsconfig.json app.ts math.ts

or, in a more generic way:

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