feat: add --git-changed option to pass the changed files according to git (#142)

Author: mondeja

bin/cli.js

@@ -3,6 +3,7 @@
  * @fileoverview The CLI that is executed from a terminal.
  * Acts as an interface to the JS API
  */
+import {exec} from 'node:child_process';
 import path from 'node:path';
 import process from 'node:process';
 import {glob} from 'glob';
@@ -54,7 +55,8 @@ const cli = meow(
             ${chalk.bold('--debug,  -d')}  Show debug logs
             ${chalk.bold('--ci, -C')}      Only output to stdout once, when linting is finished
             ${chalk.bold('--stdin')}       Read an SVG from stdin
-            ${chalk.bold('--summary')}     Print the summary at the end (default)`,
+            ${chalk.bold('--summary')}     Print the summary at the end (default)
+            ${chalk.bold('--git-changed')} Only lint files that have changed according to git`,
 	{
 		importMeta: import.meta,
 		flags: {
@@ -73,6 +75,33 @@ process.on('exit', () => {
 	gui.finish();
 });
 
+/**
+ * Load files based on input and/or git changed files
+ * @param {string} input CLI input files
+ * @param {boolean} gitChanged Whether to load changed files from git
+ * @returns {Promise<string[]>} A promise that resolves to an array of file paths
+ */
+const loadInputFiles = (input, gitChanged) =>
+	new Promise((resolve, reject) => {
+		const files = input ?? [];
+		if (gitChanged) {
+			exec(
+				"git diff --cached --name-only --diff-filter=ACM '**/*.svg'",
+				(error, stdout) => {
+					if (error) {
+						reject(error);
+						return;
+					}
+
+					const allFiles = [...files, ...stdout.split('\n').filter(Boolean)];
+					resolve(allFiles);
+				},
+			);
+		} else {
+			resolve(files);
+		}
+	});
+
 /** CLI main function */
 // eslint-disable-next-line unicorn/prefer-top-level-await
 (async function () {
@@ -145,7 +174,8 @@ process.on('exit', () => {
 		// Lint all the CLI specified files
 		const ignore = configObject.ignore || [];
 		delete configObject.ignore; // Remove ignore from config to avoid passing it to SVGLint
-		const files = cli.input
+		const inputFiles = await loadInputFiles(cli.input, cli.flags.gitChanged);
+		const files = inputFiles
 			.flatMap((v) => glob.sync(v, {ignore}))
 			.map((v) => path.resolve(process.cwd(), v));