feat(indent): support TSTypeAliasDeclaration (#796)

shixianqin · 9romise · web-flow · commit c62afeab8695 · 2025-07-01T23:38:30.000Z
Co-authored-by: Vida Xie &lt;38204901+9romise@users.noreply.github.com&gt;
Co-authored-by: Vida Xie &lt;vida_2020@163.com&gt;
diff --git a/packages/eslint-plugin/rules/indent/indent._ts_.test.ts b/packages/eslint-plugin/rules/indent/indent._ts_.test.ts
@@ -827,6 +827,13 @@ const map2 = Object.keys(map)
       `,
       options: [2],
     },
+    $`
+      type Foo = string
+      declare type Foo = number
+      namespace Foo {
+          type Bar = boolean
+      }
+    `,
     {
       code: $`
         using a = foo(),
@@ -2115,6 +2122,27 @@ class Foo {
         },
       ],
     },
+    {
+      code: $`
+         type A = number
+          declare type B = number
+        namespace Foo {
+              declare type C = number
+        }
+      `,
+      output: $`
+        type A = number
+        declare type B = number
+        namespace Foo {
+            declare type C = number
+        }
+      `,
+      errors: [
+        { messageId: 'wrongIndentation', data: { expected: '0 spaces', actual: 1 }, line: 1, column: 1 },
+        { messageId: 'wrongIndentation', data: { expected: '0 spaces', actual: 2 }, line: 2, column: 1 },
+        { messageId: 'wrongIndentation', data: { expected: '4 spaces', actual: 6 }, line: 4, column: 1 },
+      ],
+    },
     {
       code: $`
         using a = foo(),
diff --git a/packages/eslint-plugin/rules/indent/indent.ts b/packages/eslint-plugin/rules/indent/indent.ts
@@ -149,6 +149,7 @@ const KNOWN_NODES = new Set([
   AST_NODE_TYPES.TSRestType,
   AST_NODE_TYPES.TSThisType,
   AST_NODE_TYPES.TSTupleType,
+  AST_NODE_TYPES.TSTypeAliasDeclaration,
   AST_NODE_TYPES.TSTypeAnnotation,
   AST_NODE_TYPES.TSTypeLiteral,
   AST_NODE_TYPES.TSTypeOperator,
@@ -1123,6 +1124,15 @@ export default createRule<RuleOptions, MessageIds>({
 
     const ignoredNodeFirstTokens = new Set<Token>()
 
+    function checkDeclarator(node: Tree.VariableDeclarator | Tree.TSTypeAliasDeclaration, equalOperator: Token) {
+      const tokenAfterOperator = sourceCode.getTokenAfter(equalOperator)!
+
+      offsets.ignoreToken(equalOperator)
+      offsets.ignoreToken(tokenAfterOperator)
+      offsets.setDesiredOffsets([tokenAfterOperator.range[0], node.range[1]], equalOperator, 1)
+      offsets.setDesiredOffset(equalOperator, sourceCode.getLastToken(node.id), 0)
+    }
+
     function checkArrayLikeNode(node: Tree.ArrayExpression | Tree.ArrayPattern | Tree.TSTupleType) {
       const elementList = node.type === AST_NODE_TYPES.TSTupleType ? node.elementTypes : node.elements
       const openingBracket = sourceCode.getFirstToken(node)!
@@ -1815,12 +1825,8 @@ export default createRule<RuleOptions, MessageIds>({
       VariableDeclarator(node) {
         if (node.init) {
           const equalOperator = sourceCode.getTokenBefore(node.init, isNotOpeningParenToken)!
-          const tokenAfterOperator = sourceCode.getTokenAfter(equalOperator)!
 
-          offsets.ignoreToken(equalOperator)
-          offsets.ignoreToken(tokenAfterOperator)
-          offsets.setDesiredOffsets([tokenAfterOperator.range[0], node.range[1]], equalOperator, 1)
-          offsets.setDesiredOffset(equalOperator, sourceCode.getLastToken(node.id), 0)
+          checkDeclarator(node, equalOperator)
         }
       },
 
@@ -1953,6 +1959,12 @@ export default createRule<RuleOptions, MessageIds>({
         checkMemberExpression(node, node.object, node.property)
       },
 
+      TSTypeAliasDeclaration(node) {
+        const equalOperator = sourceCode.getTokenBefore(node.typeAnnotation, isNotOpeningParenToken)!
+
+        checkDeclarator(node, equalOperator)
+      },
+
       'TSTupleType': checkArrayLikeNode,
 
       TSEnumDeclaration(node) {
