feat(prompt-cli): add standalone prompt interface

@commitlint/prompt-cli/cli.js

@@ -0,0 +1,29 @@
+#!/usr/bin/env node
+const execa = require('execa');
+const meow = require('meow');
+const prompter = require('@commitlint/prompt').prompter;
+
+const HELP = `
+	Usage
+		$ commit
+`;
+
+const _ = undefined;
+const prompt = () => prompter(_, commit);
+
+main(meow(HELP))
+	.catch(err => {
+		setTimeout(() => {
+			throw err;
+		});
+	});
+
+function main() {
+	return prompt();
+}
+
+function commit(message) {
+	const c = execa('git', ['commit', '-m', message]);
+	c.stdout.pipe(process.stdout);
+	c.stderr.pipe(process.stderr);
+}

@commitlint/prompt-cli/package.json

@@ -0,0 +1,36 @@
+{
+  "name": "@commitlint/prompt",
+  "version": "3.0.0",
+  "description": "commit prompt using .commitlintrc",
+  "bin": {
+    "commit": "./cli.js"
+  },
+  "scripts": {
+    "clean": "rimraf lib",
+    "commit": "$npm_package_bin_commit",
+    "pretest": "dep-check"
+  },
+  "xo": false,
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/marionebl/commitlint.git"
+  },
+  "keywords": [
+    "commitlint",
+    "prompt"
+  ],
+  "author": "Mario Nebl <hello@herebecode.com>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/marionebl/commitlint/issues"
+  },
+  "homepage": "https://github.com/marionebl/commitlint#readme",
+  "devDependencies": {
+    "@commitlint/utils": "^3.0.0"
+  },
+  "dependencies": {
+    "@commitlint/prompt": "^3.0.0",
+    "execa": "^0.7.0",
+    "meow": "^3.7.0"
+  }
+}

@commitlint/prompt-cli/readme.md

@@ -0,0 +1,15 @@
+> commit prompt using .commitlintrc
+
+# @commitlint/prompt-cli
+
+## Getting started
+
+```bash
+npm install --g @commitlint/prompt-cli @commitlint/config-angular
+echo '{"extends": ["@commitlint/config-angular"]}' > .commitlintrc
+```
+
+```bash
+git add .
+commit
+```