Support commitlint.config.ts with TypeScript

Expected Behavior

Commitlint should be able to parse the config file written in TypeScript

Current Behavior

Commitlint asks me to add a config file

> git ls-files --stage -- C:\Users\.....(reducted)......\commitlint.config.ts
⧗   input: Add commitlint and husky
✖   Please add rules to your `commitlint.config.js`
    - Getting started guide: https://git.io/fhHij
    - Example config: https://git.io/fhHip [empty-rules]

✖   found 1 problems, 0 warnings
ⓘ   Get help: https://github.com/conventional-changelog/commitlint/#what-is-commitlint

husky - commit-msg hook exited with code 1 (error)

Affected packages

• cli
• core
• prompt
• config-angular

Steps to Reproduce (for bugs)

1. Install
2. Add commitlint.config.ts
3. Perform an unconventional commit
4. See Git log

commitlint.config.ts

export default { extends: ['@commitlint/config-conventional'] };

Context

Well, I want my repo to have only TS files rather than combining with JS files- including config files on my repository and I need Commitlint would also respect this choice.

Your Environment

Executable	Version
commitlint --version	12.1.4
git --version	2.31.1.windows.1
node --version	v14.16.1

[polkovnikov-ph]

Somehow documentation already mentions using TypeScript for configuration, yet it’s unclear how to use it.

[polkovnikov-ph]

when commitlint.config.js does not exist

@songhn233 If someone accidentally used tsc on all *.ts files, including commitlint.config.ts, now changes to commitlint.config.ts would be magically ignored.

Common resolution strategy is

• run .ts config if exists, error if no ts-node around;
• run .js config if exists;
• use default config.