fix(snippet): dedent of a single-line region, close #1686

__tests__/unit/node/markdown/plugins/snippet.test.ts

@@ -0,0 +1,60 @@
+import { dedent } from 'node/markdown/plugins/snippet'
+
+describe('node/markdown/plugins/snippet', () => {
+  describe('dedent', () => {
+    test('when 0-level is minimal, do not remove spaces', () => {
+      expect(
+        dedent(
+          [
+            //
+            'fn main() {',
+            '  println!("Hello");',
+            '}'
+          ].join('\n')
+        )
+      ).toMatchInlineSnapshot(`
+        "fn main() {
+          println!(\\"Hello\\");
+        }"
+      `)
+    })
+
+    test('when 4-level is minimal, remove 4 spaces', () => {
+      expect(
+        dedent(
+          [
+            //
+            '    let a = {',
+            '        value: 42',
+            '    };'
+          ].join('\n')
+        )
+      ).toMatchInlineSnapshot(`
+        "let a = {
+            value: 42
+        };"
+      `)
+    })
+
+    test('when only 1 line is passed, dedent it', () => {
+      expect(dedent('    let a = 42;')).toEqual('let a = 42;')
+    })
+
+    test('handle tabs as well', () => {
+      expect(
+        dedent(
+          [
+            //
+            '	let a = {',
+            '		value: 42',
+            '	};'
+          ].join('\n')
+        )
+      ).toMatchInlineSnapshot(`
+        "let a = {
+        	value: 42
+        };"
+      `)
+    })
+  })
+})

package.json

@@ -68,6 +68,7 @@
     "test-build": "VITE_TEST_BUILD=1 pnpm test-preview",
     "debug-preview": "DEBUG=1 vitest -r __tests__/e2e",
     "debug-build": "VITE_TEST_BUILD=1 pnpm debug-preview",
+    "unit-dev": "vitest -r __tests__/unit",
     "e2e-dev": "wait-on -d 100 dist/node/cli.js && node ./bin/vitepress dev __tests__/e2e",
     "changelog": "conventional-changelog -p angular -i CHANGELOG.md -s",
     "release": "node scripts/release.js",

src/node/markdown/plugins/snippet.ts

@@ -3,29 +3,18 @@ import path from 'path'
 import MarkdownIt from 'markdown-it'
 import { RuleBlock } from 'markdown-it/lib/parser_block'
 
-function dedent(text: string) {
-  const wRegexp = /^([ \t]*)(.*)\n/gm
-  let match
-  let minIndentLength = null
-
-  while ((match = wRegexp.exec(text)) !== null) {
-    const [indentation, content] = match.slice(1)
-    if (!content) continue
-
-    const indentLength = indentation.length
-    if (indentLength > 0) {
-      minIndentLength =
-        minIndentLength !== null
-          ? Math.min(minIndentLength, indentLength)
-          : indentLength
-    } else break
-  }
+export function dedent(text: string): string {
+  const lines = text.split('\n')
+
+  const minIndentLength = lines.reduce((acc, line) => {
+    for (let i = 0; i < line.length; i++) {
+      if (line[i] !== ' ' && line[i] !== '\t') return Math.min(i, acc)
+    }
+    return acc
+  }, Infinity)
 
-  if (minIndentLength) {
-    text = text.replace(
-      new RegExp(`^[ \t]{${minIndentLength}}(.*)`, 'gm'),
-      '$1'
-    )
+  if (minIndentLength < Infinity) {
+    return lines.map((x) => x.slice(minIndentLength)).join('\n')
   }
 
   return text