fix(eslint-plugin): crash fixing readonly arrays to generic (#1172)

a-tarasyuk · bradzacher · commit 2b2f2d7f4702 · 2019-11-05T08:19:58.000-08:00
diff --git a/packages/eslint-plugin/src/rules/array-type.ts b/packages/eslint-plugin/src/rules/array-type.ts
@@ -146,7 +146,8 @@ export default util.createRule<Options, MessageIds>({
         return false;
       }
 
-      if (node.range[0] - prevToken.range[1] > 0) {
+      const nextToken = sourceCode.getTokenAfter(prevToken);
+      if (nextToken && sourceCode.isSpaceBetweenTokens(prevToken, nextToken)) {
         return false;
       }
 
@@ -168,6 +169,21 @@ export default util.createRule<Options, MessageIds>({
       return 'T';
     }
 
+    /**
+     * @param node the node to be evaluated
+     */
+    function getTypeOpNodeRange(
+      node: TSESTree.Node | null,
+    ): [number, number] | undefined {
+      if (!node) {
+        return undefined;
+      }
+
+      const firstToken = sourceCode.getFirstToken(node)!;
+      const nextToken = sourceCode.getTokenAfter(firstToken)!;
+      return [firstToken.range[0], nextToken.range[0]];
+    }
+
     return {
       TSArrayType(node): void {
         if (
@@ -208,24 +224,27 @@ export default util.createRule<Options, MessageIds>({
             type: getMessageType(node.elementType),
           },
           fix(fixer) {
-            const startText = requireWhitespaceBefore(node);
             const toFix = [
               fixer.replaceTextRange([node.range[1] - 2, node.range[1]], '>'),
-              fixer.insertTextBefore(
-                node,
-                `${startText ? ' ' : ''}${isReadonly ? 'Readonly' : ''}Array<`,
-              ),
             ];
-            if (typeOpNode) {
-              // remove the readonly operator if it exists
-              toFix.unshift(
-                fixer.removeRange([
-                  typeOpNode.range[0],
-                  typeOpNode.range[0] + 'readonly '.length,
-                ]),
+            const startText = requireWhitespaceBefore(node);
+            const typeOpNodeRange = getTypeOpNodeRange(typeOpNode);
+
+            if (typeOpNodeRange) {
+              toFix.unshift(fixer.removeRange(typeOpNodeRange));
+            } else {
+              toFix.push(
+                fixer.insertTextBefore(node, `${startText ? ' ' : ''}`),
               );
             }
 
+            toFix.push(
+              fixer.insertTextBefore(
+                node,
+                `${isReadonly ? 'Readonly' : ''}Array<`,
+              ),
+            );
+
             if (node.elementType.type === AST_NODE_TYPES.TSParenthesizedType) {
               const first = sourceCode.getFirstToken(node.elementType);
               const last = sourceCode.getLastToken(node.elementType);
diff --git a/packages/eslint-plugin/tests/rules/array-type.test.ts b/packages/eslint-plugin/tests/rules/array-type.test.ts
@@ -1071,5 +1071,35 @@ class Foo<T = Bar[][]> extends Bar<T, T[]> implements Baz<T[]> {
       `let a: readonly Array<number>[] = []`,
       'array',
     );
+    testOutput(
+      'generic',
+      `type T = readonly(string)[]`,
+      `type T = ReadonlyArray<string>`,
+      'generic',
+    );
+    testOutput(
+      'generic',
+      `let a: readonly(readonly string[])[] = []`,
+      `let a: ReadonlyArray<ReadonlyArray<string>> = []`,
+      'generic',
+    );
+    testOutput(
+      'generic',
+      `type T = readonly(readonly string[])[]`,
+      `type T = ReadonlyArray<ReadonlyArray<string>>`,
+      'generic',
+    );
+    testOutput(
+      'generic',
+      `type T = readonly (readonly string[])[]`,
+      `type T = ReadonlyArray<ReadonlyArray<string>>`,
+      'generic',
+    );
+    testOutput(
+      'generic',
+      `type T = readonly    (readonly string[])[]`,
+      `type T = ReadonlyArray<ReadonlyArray<string>>`,
+      'generic',
+    );
   });
 });
