From 430d628b0271718e2df470831832fa40b41150be Mon Sep 17 00:00:00 2001
From: Brad Zacher <brad.zacher@gmail.com>
Date: Fri, 28 Jun 2019 08:32:19 -0700
Subject: [PATCH] fix(eslint-plugin): handle `const;` (#633)

Fixes #441
---
 .../src/rules/consistent-type-definitions.ts             | 1 -
 .../src/rules/indent-new-do-not-use/index.ts             | 4 ++++
 packages/eslint-plugin/src/rules/indent.ts               | 9 +++++++++
 packages/eslint-plugin/src/rules/prefer-for-of.ts        | 5 ++++-
 packages/eslint-plugin/tests/rules/indent/indent.test.ts | 2 ++
 packages/typescript-estree/src/ts-estree/ts-estree.ts    | 1 +
 6 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/packages/eslint-plugin/src/rules/consistent-type-definitions.ts b/packages/eslint-plugin/src/rules/consistent-type-definitions.ts
index d8d9bb675a2..eea12b9cf84 100644
--- a/packages/eslint-plugin/src/rules/consistent-type-definitions.ts
+++ b/packages/eslint-plugin/src/rules/consistent-type-definitions.ts
@@ -27,7 +27,6 @@ export default util.createRule({
     const sourceCode = context.getSourceCode();
 
     return {
-      // VariableDeclaration with kind type has only one VariableDeclarator
       "TSTypeAliasDeclaration[typeAnnotation.type='TSTypeLiteral']"(
         node: TSESTree.TSTypeAliasDeclaration,
       ) {
diff --git a/packages/eslint-plugin/src/rules/indent-new-do-not-use/index.ts b/packages/eslint-plugin/src/rules/indent-new-do-not-use/index.ts
index 14088c55378..70cf1c37919 100644
--- a/packages/eslint-plugin/src/rules/indent-new-do-not-use/index.ts
+++ b/packages/eslint-plugin/src/rules/indent-new-do-not-use/index.ts
@@ -1382,6 +1382,10 @@ export default createRule<Options, MessageIds>({
       },
 
       VariableDeclaration(node) {
+        if (node.declarations.length === 0) {
+          return;
+        }
+
         let variableIndent = Object.prototype.hasOwnProperty.call(
           options.VariableDeclarator,
           node.kind,
diff --git a/packages/eslint-plugin/src/rules/indent.ts b/packages/eslint-plugin/src/rules/indent.ts
index 6b2a83066dd..321f32f4cce 100644
--- a/packages/eslint-plugin/src/rules/indent.ts
+++ b/packages/eslint-plugin/src/rules/indent.ts
@@ -175,6 +175,15 @@ export default util.createRule<Options, MessageIds>({
         }
       },
 
+      VariableDeclaration(node: TSESTree.VariableDeclaration) {
+        // https://github.com/typescript-eslint/typescript-eslint/issues/441
+        if (node.declarations.length === 0) {
+          return;
+        }
+
+        return rules.VariableDeclaration(node);
+      },
+
       TSAsExpression(node: TSESTree.TSAsExpression) {
         // transform it to a BinaryExpression
         return rules['BinaryExpression, LogicalExpression']({
diff --git a/packages/eslint-plugin/src/rules/prefer-for-of.ts b/packages/eslint-plugin/src/rules/prefer-for-of.ts
index 19551a91166..89f6c540303 100644
--- a/packages/eslint-plugin/src/rules/prefer-for-of.ts
+++ b/packages/eslint-plugin/src/rules/prefer-for-of.ts
@@ -186,8 +186,11 @@ export default util.createRule({
           return;
         }
 
-        const [declarator] = node.init.declarations;
+        const declarator = node.init.declarations[0] as
+          | TSESTree.VariableDeclarator
+          | undefined;
         if (
+          !declarator ||
           !isZeroInitialized(declarator) ||
           declarator.id.type !== AST_NODE_TYPES.Identifier
         ) {
diff --git a/packages/eslint-plugin/tests/rules/indent/indent.test.ts b/packages/eslint-plugin/tests/rules/indent/indent.test.ts
index e992b440c6c..9fb9ef7dadd 100644
--- a/packages/eslint-plugin/tests/rules/indent/indent.test.ts
+++ b/packages/eslint-plugin/tests/rules/indent/indent.test.ts
@@ -768,6 +768,8 @@ const div: JQuery<HTMLElement> = $('<div>')
             `,
       options: [2, { VariableDeclarator: { const: 3 } }],
     },
+    // https://github.com/typescript-eslint/typescript-eslint/issues/441
+    `const;`,
   ],
   invalid: [
     ...individualNodeTests.invalid,
diff --git a/packages/typescript-estree/src/ts-estree/ts-estree.ts b/packages/typescript-estree/src/ts-estree/ts-estree.ts
index e786e83e0df..8eed48390d0 100644
--- a/packages/typescript-estree/src/ts-estree/ts-estree.ts
+++ b/packages/typescript-estree/src/ts-estree/ts-estree.ts
@@ -1387,6 +1387,7 @@ export interface UnaryExpression extends UnaryExpressionBase {
 
 export interface VariableDeclaration extends BaseNode {
   type: AST_NODE_TYPES.VariableDeclaration;
+  // NOTE - this is not guaranteed to have any elements in it. i.e. `const;`
   declarations: VariableDeclarator[];
   kind: 'let' | 'const' | 'var';
   declare?: boolean;