fix(typescript-estree): handle TS4.0 breaking change in TupleType (#2197

)
typescript-eslint · Jun 9, 2020 · 5d68129 · 5d68129
1 parent a2ffe55
commit 5d68129
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diff --git a/.prettierignore b/.prettierignore
@@ -5,6 +5,7 @@
 **/shared-fixtures
 **/.vscode
 **/.nyc_output
+**/.vs
 packages/eslint-plugin-tslint/tests/test-tslint-rules-directory/alwaysFailRule.js
 .github
 packages/eslint-plugin/src/configs/*.json

diff --git a/packages/typescript-estree/src/convert.ts b/packages/typescript-estree/src/convert.ts
@@ -2617,9 +2617,16 @@ export class Converter {
         });
       }
       case SyntaxKind.TupleType: {
+        // In TS 4.0, the `elementTypes` property was changed to `elements`.
+        // To support both at compile time, we cast to access the newer version
+        // if the former does not exist.
+        const elementTypes = node.elementTypes
+          ? node.elementTypes.map(el => this.convertType(el))
+          : (node as any).elements.map((el: ts.Node) => this.convertType(el));
+
         return this.createNode<TSESTree.TSTupleType>(node, {
           type: AST_NODE_TYPES.TSTupleType,
-          elementTypes: node.elementTypes.map(el => this.convertType(el)),
+          elementTypes,
         });
       }
       case SyntaxKind.UnionType: {