fix(immutable-data): ignore casting when evaluating the expressions (#792)

fix #790

Author: RebeccaStevens

src/rules/immutable-data.ts

@@ -40,6 +40,7 @@ import {
   isMemberExpression,
   isNewExpression,
   isObjectConstructorType,
+  isTSAsExpression,
 } from "#eslint-plugin-functional/utils/type-guards";
 
 /**
@@ -361,62 +362,66 @@ function checkUpdateExpression(
  * a mutator method call.
  */
 function isInChainCallAndFollowsNew(
-  node: TSESTree.MemberExpression,
+  node: TSESTree.Expression,
   context: Readonly<RuleContext<keyof typeof errorMessages, Options>>,
 ): boolean {
+  if (isMemberExpression(node)) {
+    return isInChainCallAndFollowsNew(node.object, context);
+  }
+
+  if (isTSAsExpression(node)) {
+    return isInChainCallAndFollowsNew(node.expression, context);
+  }
+
   // Check for: [0, 1, 2]
-  if (isArrayExpression(node.object)) {
+  if (isArrayExpression(node)) {
     return true;
   }
 
   // Check for: new Array()
   if (
-    isNewExpression(node.object) &&
-    isArrayConstructorType(getTypeOfNode(node.object.callee, context))
+    isNewExpression(node) &&
+    isArrayConstructorType(getTypeOfNode(node.callee, context))
   ) {
     return true;
   }
 
   if (
-    isCallExpression(node.object) &&
-    isMemberExpression(node.object.callee) &&
-    isIdentifier(node.object.callee.property)
+    isCallExpression(node) &&
+    isMemberExpression(node.callee) &&
+    isIdentifier(node.callee.property)
   ) {
     // Check for: Array.from(iterable)
     if (
-      arrayConstructorFunctions.some(
-        isExpected(node.object.callee.property.name),
-      ) &&
-      isArrayConstructorType(getTypeOfNode(node.object.callee.object, context))
+      arrayConstructorFunctions.some(isExpected(node.callee.property.name)) &&
+      isArrayConstructorType(getTypeOfNode(node.callee.object, context))
     ) {
       return true;
     }
 
     // Check for: array.slice(0)
     if (
-      arrayNewObjectReturningMethods.some(
-        isExpected(node.object.callee.property.name),
-      )
+      arrayNewObjectReturningMethods.some(isExpected(node.callee.property.name))
     ) {
       return true;
     }
 
     // Check for: Object.entries(object)
     if (
       objectConstructorNewObjectReturningMethods.some(
-        isExpected(node.object.callee.property.name),
+        isExpected(node.callee.property.name),
       ) &&
-      isObjectConstructorType(getTypeOfNode(node.object.callee.object, context))
+      isObjectConstructorType(getTypeOfNode(node.callee.object, context))
     ) {
       return true;
     }
 
     // Check for: "".split("")
     if (
       stringConstructorNewObjectReturningMethods.some(
-        isExpected(node.object.callee.property.name),
+        isExpected(node.callee.property.name),
       ) &&
-      getTypeOfNode(node.object.callee.object, context).isStringLiteral()
+      getTypeOfNode(node.callee.object, context).isStringLiteral()
     ) {
       return true;
     }

src/utils/misc.ts

@@ -12,6 +12,7 @@ import {
   isMemberExpression,
   isPrivateIdentifier,
   isThisExpression,
+  isTSAsExpression,
   isTSTypeAnnotation,
   isUnaryExpression,
   isVariableDeclaration,
@@ -72,7 +73,9 @@ function getNodeIdentifierText(
                     ? context.sourceCode
                         .getText(node.typeAnnotation as TSESTree.Node)
                         .replaceAll(/\s+/gmu, "")
-                    : null;
+                    : isTSAsExpression(node)
+                      ? getNodeIdentifierText(node.expression, context)
+                      : null;
 
   if (identifierText !== null) {
     return identifierText;

src/utils/type-guards.ts

@@ -237,6 +237,12 @@ export function isTSArrayType(
   return node.type === AST_NODE_TYPES.TSArrayType;
 }
 
+export function isTSAsExpression(
+  node: TSESTree.Node,
+): node is TSESTree.TSAsExpression {
+  return node.type === AST_NODE_TYPES.TSAsExpression;
+}
+
 export function isTSFunctionType(
   node: TSESTree.Node,
 ): node is TSESTree.TSFunctionType {

tests/rules/immutable-data/ts/array/invalid.ts

@@ -795,6 +795,20 @@ const tests: Array<
       },
     ],
   },
+  {
+    code: dedent`
+      (mutable_foo as string[]).sort();
+    `,
+    optionsSet: [[]],
+    errors: [
+      {
+        messageId: "array",
+        type: AST_NODE_TYPES.CallExpression,
+        line: 1,
+        column: 1,
+      },
+    ],
+  },
 ];
 
 export default tests;

tests/rules/immutable-data/ts/array/valid.ts

@@ -338,6 +338,18 @@ const tests: Array<ValidTestCaseSet<OptionsOf<typeof rule>>> = [
     `,
     optionsSet: [[{ ignoreImmediateMutation: true }]],
   },
+  {
+    code: dedent`
+      (mutable_foo as string[]).sort();
+    `,
+    optionsSet: [[{ ignoreAccessorPattern: "mutable*" }]],
+  },
+  {
+    code: dedent`
+      ([a, b, c] as string[]).sort();
+    `,
+    optionsSet: [[{ ignoreImmediateMutation: true }]],
+  },
 ];
 
 export default tests;

tests/rules/immutable-data/ts/object/invalid.ts

@@ -511,6 +511,20 @@ const tests: Array<
       },
     ],
   },
+  {
+    code: dedent`
+      (mutable_foo as Bar).baz = "hello world";
+    `,
+    optionsSet: [[]],
+    errors: [
+      {
+        messageId: "generic",
+        type: AST_NODE_TYPES.AssignmentExpression,
+        line: 1,
+        column: 1,
+      },
+    ],
+  },
 ];
 
 export default tests;

tests/rules/immutable-data/ts/object/valid.ts

@@ -195,6 +195,12 @@ const tests: Array<ValidTestCaseSet<OptionsOf<typeof rule>>> = [
     `,
     optionsSet: [[{ ignoreNonConstDeclarations: true }]],
   },
+  {
+    code: dedent`
+      (mutable_foo as Bar).baz = "hello world";
+    `,
+    optionsSet: [[{ ignoreAccessorPattern: "mutable*.*" }]],
+  },
 ];
 
 export default tests;