add skipTemplateStartIndent

docs/rules/indent.md

@@ -34,6 +34,34 @@ Or, for tabbed indentation:
 }
 ```
 
+Object option for template literals:
+
+```json
+{
+  "@html-eslint/indent": ["error", 2, {
+    "skipTemplateStartIndent": true  // Skip starting indent from JS code
+  }]
+}
+```
+
+### skipTemplateStartIndent
+
+When enabled, this option ignores the leading indentation from the JS code that appears before the template literal start (e.g. code on the same line as the opening backtick). This prevents the JS line's indentation from increasing the base indent level of the template content.
+
+Example with `skipTemplateStartIndent: false` (default):
+```js
+const html = /*html*/ `
+      <div>yeah</div>  // indented based on JS code's indentation
+`;
+```
+
+Example with `skipTemplateStartIndent: true`:
+```js
+const html = /*html*/ `
+<div>yeah</div>  // no extra indent from JS code
+`;
+```
+
 Examples of **incorrect** code for this rule with the default option:
 
 ```html,incorrect

packages/eslint-plugin/lib/rules/indent/indent.js

@@ -17,6 +17,7 @@
  * @typedef {"tab" | number} Option1
  * @typedef {Object} Option2
  * @property {number} [Option2.Attribute]
+ * @property {boolean} [Option2.skipTemplateStartIndent]
  * @property {Record<string, number>} [Option2.tagChildrenIndent]
  */
 
@@ -86,6 +87,15 @@ module.exports = {
             minimum: 1,
             default: 1,
           },
+          // When true, ignore the leading indentation from the JS code
+          // that appears before the template literal start (e.g. code on
+          // the same line as the opening backtick). This prevents the
+          // JS line's indentation from increasing the base indent level
+          // of the template content.
+          skipTemplateStartIndent: {
+            type: "boolean",
+            default: false,
+          },
           tagChildrenIndent: {
             default: {},
             type: "object",
@@ -164,8 +174,18 @@ module.exports = {
       // @ts-ignore
       const lineIndex = node.loc.start.line - 1;
       const line = lines[lineIndex];
-
-      const spaceCount = countLeftPadding(line);
+      // If configured to skip the starting indent of the JS code that
+      // appears before the template literal start (e.g. `let x = /*html*/ \``),
+      // then count left padding from the template literal's start column
+      // rather than the whole line. This effectively ignores the leading
+      // JS indentation for base calculation.
+      const startColumn = node.loc.start.column;
+      const relevant =
+        indentLevelOptions && indentLevelOptions.skipTemplateStartIndent
+          ? line.slice(startColumn)
+          : line;
+
+      const spaceCount = countLeftPadding(relevant);
       if (indentType === "space") {
         return Math.floor(spaceCount / indentSize) + 1;
       } else {

packages/eslint-plugin/tests/rules/indent.test.js

@@ -1648,6 +1648,55 @@ class Component extends LitElement {
 }
       `,
       output: `
+
+class Component extends LitElement {
+  render() {
+    return html\`
+      <p>content</p>
+    \`;
+  }
+}
+      `,
+      errors: wrongIndentErrors(1),
+    },
+    // Tests for skipTemplateStartIndent option
+    {
+      code: `
+let html = /*html*/ \`
+<div>yeah</div>
+\`
+      `,
+      output: `
+let html = /*html*/ \`
+  <div>yeah</div>
+\`
+      `,
+      options: [2],
+      errors: wrongIndentErrors(1),
+    },
+    {
+      code: `
+let html = /*html*/ \`
+<div>yeah</div>
+\`
+      `,
+      options: [2, { skipTemplateStartIndent: true }],
+      errors: [],
+    },
+    {
+      code: `
+const obj = {
+  nested: {
+    html: /*html*/ \`
+<div>yeah</div>
+    \`
+  }
+}`,
+      options: [2, { skipTemplateStartIndent: true }],
+      errors: [],
+    },
+    {
+      code: `
 class Component extends LitElement {
   render() {
     return html\`