refactor!(prefer-readonly-type): change checkImplicit option to be more expicit of what it does

BREAKING CHANGE: option checkImplicit changed to checkForImplicitMutableArrays

Author: RebeccaStevens

src/rules/prefer-readonly-type.ts

@@ -39,7 +39,7 @@ type Options = AllowLocalMutationOption &
   IgnoreInterfaceOption &
   IgnorePatternOption & {
     readonly allowMutableReturnType: boolean;
-    readonly checkImplicit: boolean;
+    readonly checkForImplicitMutableArrays: boolean;
     readonly ignoreCollections: boolean;
   };
 
@@ -56,7 +56,7 @@ const schema: JSONSchema4 = [
         allowMutableReturnType: {
           type: "boolean",
         },
-        checkImplicit: {
+        checkForImplicitMutableArrays: {
           type: "boolean",
         },
         ignoreCollections: {
@@ -70,7 +70,7 @@ const schema: JSONSchema4 = [
 
 // The default options for the rule.
 const defaultOptions: Options = {
-  checkImplicit: false,
+  checkForImplicitMutableArrays: false,
   ignoreClass: false,
   ignoreInterface: false,
   ignoreCollections: false,
@@ -255,7 +255,7 @@ function checkProperty(
 /**
  * Check if the given TypeReference violates this rule.
  */
-function checkImplicitType(
+function checkForImplicitMutableArray(
   node:
     | TSESTree.ArrowFunctionExpression
     | TSESTree.FunctionDeclaration
@@ -264,7 +264,7 @@ function checkImplicitType(
   context: RuleContext<keyof typeof errorMessages, Options>,
   options: Options
 ): RuleResult<keyof typeof errorMessages, Options> {
-  if (options.checkImplicit) {
+  if (options.checkForImplicitMutableArrays) {
     type Declarator = {
       readonly id: TSESTree.Node;
       readonly init: TSESTree.Node | null;
@@ -324,17 +324,17 @@ export const rule = createRule<keyof typeof errorMessages, Options>(
   meta,
   defaultOptions,
   {
-    ArrowFunctionExpression: checkImplicitType,
+    ArrowFunctionExpression: checkForImplicitMutableArray,
     ClassProperty: checkProperty,
-    FunctionDeclaration: checkImplicitType,
-    FunctionExpression: checkImplicitType,
+    FunctionDeclaration: checkForImplicitMutableArray,
+    FunctionExpression: checkForImplicitMutableArray,
     TSArrayType: checkArrayOrTupleType,
     TSIndexSignature: checkProperty,
     TSParameterProperty: checkProperty,
     TSPropertySignature: checkProperty,
     TSTupleType: checkArrayOrTupleType,
     TSMappedType: checkMappedType,
     TSTypeReference: checkTypeReference,
-    VariableDeclaration: checkImplicitType,
+    VariableDeclaration: checkForImplicitMutableArray,
   }
 );

tests/rules/prefer-readonly-type/ts/invalid.ts

@@ -507,7 +507,7 @@ const tests: ReadonlyArray<InvalidTestCase> = [
     code: dedent`
       const foo = [1, 2, 3]
       function bar(param = [1, 2, 3]) {}`,
-    optionsSet: [[{ checkImplicit: true }]],
+    optionsSet: [[{ checkForImplicitMutableArrays: true }]],
     output: dedent`
       const foo: readonly unknown[] = [1, 2, 3]
       function bar(param: readonly unknown[] = [1, 2, 3]) {}`,

tests/rules/prefer-readonly-type/ts/valid.ts

@@ -142,7 +142,7 @@ const tests: ReadonlyArray<ValidTestCase> = [
   {
     code: dedent`
     const foo = [1, 2, 3] as const`,
-    optionsSet: [[{ checkImplicit: true }]],
+    optionsSet: [[{ checkForImplicitMutableArrays: true }]],
   },
   // Should not fail on implicit Array.
   {
@@ -357,7 +357,9 @@ const tests: ReadonlyArray<ValidTestCase> = [
   },
   {
     code: dedent`const Foo = []`,
-    optionsSet: [[{ ignoreCollections: true, checkImplicit: true }]],
+    optionsSet: [
+      [{ ignoreCollections: true, checkForImplicitMutableArrays: true }],
+    ],
   },
   {
     code: dedent`type Foo = [string, string];`,
@@ -369,7 +371,9 @@ const tests: ReadonlyArray<ValidTestCase> = [
   },
   {
     code: dedent`const Foo = ['foo', 'bar'];`,
-    optionsSet: [[{ ignoreCollections: true, checkImplicit: true }]],
+    optionsSet: [
+      [{ ignoreCollections: true, checkForImplicitMutableArrays: true }],
+    ],
   },
   {
     code: dedent`type Foo = Set<string, string>;`,