Fix FP S3800 (function-return-type): Exception for sanitation functions

its/ruling/src/test/expected/jsts/vuetify/javascript-S3800.json

@@ -1,37 +1,5 @@
 {
 "vuetify:packages/docs/src/examples/v-date-picker/event-events.vue": [
 44
-],
-"vuetify:packages/docs/src/examples/v-file-input/prop-validation.vue": [
-15
-],
-"vuetify:packages/docs/src/examples/v-form/misc-vee-validate.vue": [
-59,
-64,
-69,
-74,
-79
-],
-"vuetify:packages/docs/src/examples/v-form/prop-fast-fail.vue": [
-26,
-34
-],
-"vuetify:packages/docs/src/examples/v-form/rules-required.vue": [
-19
-],
-"vuetify:packages/docs/src/examples/v-form/usage.vue": [
-54,
-59,
-67,
-72
-],
-"vuetify:packages/docs/src/examples/v-input/prop-rules.vue": [
-11
-],
-"vuetify:packages/docs/src/examples/v-text-field/misc-guide.vue": [
-61
-],
-"vuetify:packages/docs/src/examples/v-text-field/prop-validation.vue": [
-42
 ]
 }

packages/jsts/src/rules/S3800/rule.ts

@@ -28,11 +28,14 @@ import {
   getParent,
   getTypeFromTreeNode,
   isAny,
+  isBooleanTrueType,
   isRequiredParserServices,
+  isStringType,
   RuleContext,
   toEncodedMessage,
 } from '../helpers';
 import { SONAR_RUNTIME } from '../../linter/parameters';
+import { type UnionType } from 'typescript';
 
 class FunctionScope {
   private readonly returnStatements: estree.ReturnStatement[] = [];
@@ -46,6 +49,12 @@ class FunctionScope {
   }
 }
 
+const isASanitationFunction = (signature: ts.Signature) => {
+  const { types } = signature.getReturnType() as UnionType;
+
+  return types.length === 2 && types.some(isBooleanTrueType) && types.some(isStringType);
+};
+
 export const rule: Rule.RuleModule = {
   meta: {
     schema: [
@@ -74,6 +83,10 @@ export const rule: Rule.RuleModule = {
         services.esTreeNodeToTSNodeMap.get(node as TSESTree.Node) as ts.SignatureDeclaration,
       );
       if (signature && hasMultipleReturnTypes(signature, checker)) {
+        if (isASanitationFunction(signature)) {
+          return;
+        }
+
         const stmts = returnStatements.filter(
           retStmt => !isNullLike(getTypeFromTreeNode(retStmt.argument!, services)),
         );

packages/jsts/src/rules/S3800/unit.test.ts

@@ -249,6 +249,29 @@ ruleTesterTs.run(`Functions should always return the same type [ts]`, rule, {
           }
         }`,
     },
+    {
+      code: `
+        function foo() {
+          return condition ? 'str' : true;
+        }`,
+    },
+    {
+      code: `
+const sanitize = () => {
+  return condition ? true : 'Value should be a string';
+};
+`,
+    },
+    {
+      code: `
+const sanitize = () => {
+  if (condition) {
+    return true;
+  };
+
+  return 'Value should be a string';
+}`,
+    },
   ],
   invalid: [
     {
@@ -468,13 +491,6 @@ ruleTesterTs.run(`Functions should always return the same type [ts]`, rule, {
         },
       ],
     },
-    {
-      code: `
-        function foo() {
-          return condition ? 'str' : true;
-        }`,
-      errors: 1,
-    },
     {
       code: `
         class C {
@@ -533,6 +549,14 @@ ruleTesterTs.run(`Functions should always return the same type [ts]`, rule, {
         },
       ],
     },
+    {
+      code: `
+const sanitize = () => {
+  return condition ? true : 42;
+};
+`,
+      errors: 1,
+    },
   ],
 });
 

packages/jsts/src/rules/helpers/type.ts

@@ -281,3 +281,13 @@ export function isTypeAlias(node: TSESTree.TypeNode, context: Rule.RuleContext)
   const variable = getVariableFromScope(scope, node.typeName.name);
   return variable?.defs.some(def => def.node.type === 'TSTypeAliasDeclaration');
 }
+
+export function isBooleanLiteralType(type: ts.Type): type is ts.Type & {
+  intrinsicName: 'true' | 'false';
+} {
+  return type.flags === ts.TypeFlags.BooleanLiteral;
+}
+
+export function isBooleanTrueType(type: ts.Type) {
+  return isBooleanLiteralType(type) && type.intrinsicName === 'true';
+}