[Fix] no-unused-prop-types with typescript eslint parser

lib/util/propTypes.js

@@ -4,6 +4,8 @@
 
 'use strict';
 
+const flatMap = require('array.prototype.flatmap');
+
 const annotations = require('./annotations');
 const propsUtil = require('./props');
 const variableUtil = require('./variable');
@@ -281,6 +283,47 @@ module.exports = function propTypesInstructions(context, components, utils) {
     return ignorePropsValidation;
   }
 
+  function declarePropTypesForTSTypeAnnotation(propTypes, declaredPropTypes) {
+    let foundDeclaredPropertiesList = [];
+    if (propTypes.typeAnnotation.type === 'TSTypeReference') {
+      const typeName = propTypes.typeAnnotation.typeName.name;
+      if (!typeName) {
+        return true;
+      }
+      // the game here is to find the type declaration in the code
+      const candidateTypes = context.getSourceCode().ast.body.filter((item) => item.type === 'VariableDeclaration' && item.kind === 'type');
+      const declarations = flatMap(candidateTypes, (type) => type.declarations);
+
+      // we tried to find either an interface or a type with the TypeReference name
+      const typeDeclaration = declarations.find((dec) => dec.id.name === typeName);
+      const interfaceDeclaration = context.getSourceCode().ast.body.find((item) => item.type === 'TSInterfaceDeclaration' && item.id.name === typeName);
+
+      if (typeDeclaration) {
+        foundDeclaredPropertiesList = typeDeclaration.init.members;
+      } else if (interfaceDeclaration) {
+        foundDeclaredPropertiesList = interfaceDeclaration.body.body;
+      } else {
+        // type not found, for example can be an exported type, etc. Can issue a warning in the future.
+        return true;
+      }
+    } else if (propTypes.typeAnnotation.type === 'TSTypeLiteral') {
+      foundDeclaredPropertiesList = propTypes.typeAnnotation.members;
+    } else {
+      // weird cases such as TSTypeFunction
+      return true;
+    }
+
+    foundDeclaredPropertiesList.forEach((tsPropertySignature) => {
+      declaredPropTypes[tsPropertySignature.key.name] = {
+        fullName: tsPropertySignature.key.name,
+        name: tsPropertySignature.key.name,
+        node: tsPropertySignature,
+        isRequired: !tsPropertySignature.optional
+      };
+    });
+    return false;
+  }
+
   /**
    * Marks all props found inside IntersectionTypeAnnotation as declared.
    * Since InterSectionTypeAnnotations can be nested, this handles recursively.
@@ -547,6 +590,9 @@ module.exports = function propTypesInstructions(context, components, utils) {
           ignorePropsValidation = true;
         }
         break;
+      case 'TSTypeAnnotation':
+        ignorePropsValidation = declarePropTypesForTSTypeAnnotation(propTypes, declaredPropTypes);
+        break;
       case null:
         break;
       default:

package.json

@@ -29,6 +29,7 @@
   "bugs": "https://github.com/yannickcr/eslint-plugin-react/issues",
   "dependencies": {
     "array-includes": "^3.1.1",
+    "array.prototype.flatmap": "^1.2.3",
     "doctrine": "^2.1.0",
     "has": "^1.0.3",
     "jsx-ast-utils": "^2.4.1",

tests/lib/rules/no-unused-prop-types.js

@@ -3211,6 +3211,42 @@ ruleTester.run('no-unused-prop-types', rule, {
         'export default Thing;'
       ].join('\n'),
       parser: parsers.TYPESCRIPT_ESLINT
+    },
+    // this test checks that there is no crash if no declaration is found (TSTypeLiteral).
+    {
+      code: [
+        'const Hello = (props: {firstname: string, lastname: string}) => {',
+        '    return <div {...props}></div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT
+    },
+    // this test checks that there is no crash if no declaration is found (TSTypeReference).
+    {
+      code: [
+        'const Hello = (props: UnfoundProps) => {',
+        '    return <div {...props}></div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT
+    },
+    {
+      // Omit, etc, cannot be handled, but must not trigger an error
+      code: [
+        'const Hello = (props: Omit<{a: string, b: string, c: string}, "a">) => {',
+        '    return <div>{props.b}</div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT
+    },
+    {
+      // neither TSTypeReference or TSTypeLiteral, we do nothing. Weird case
+      code: [
+        'const Hello = (props: () => any) => {',
+        '    return <div>{props.firstname}</div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT
     }
   ],
 
@@ -5312,6 +5348,97 @@ ruleTester.run('no-unused-prop-types', rule, {
       }, {
         message: '\'thisPropsPropUnused\' PropType is defined but prop is never used'
       }]
+    }, {
+      code: [
+        'type Person = {',
+        '  lastname: string',
+        '};',
+        'const Hello = (props: Person) => {',
+        '    return <div>Hello {props.firstname}</div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.BABEL_ESLINT,
+      errors: [{
+        message: '\'lastname\' PropType is defined but prop is never used'
+      }]
+    }, {
+      code: [
+        'type Person = {',
+        '  lastname: string',
+        '};',
+        'const Hello = (props: Person) => {',
+        '    return <div>Hello {props.firstname}</div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT,
+      errors: [
+        {
+          message: '\'lastname\' PropType is defined but prop is never used'
+        }
+      ]
+    },
+    {
+      code: [
+        'type Person = {',
+        '  lastname?: string',
+        '};',
+        'const Hello = (props: Person) => {',
+        '    return <div>Hello {props.firstname}</div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT,
+      errors: [
+        {
+          message: '\'lastname\' PropType is defined but prop is never used'
+        }
+      ]
+    },
+    {
+      code: [
+        'type Person = {',
+        '  firstname: string',
+        '  lastname: string',
+        '};',
+        'const Hello = ({firstname}: Person) => {',
+        '    return <div>Hello {firstname}</div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT,
+      errors: [
+        {
+          message: '\'lastname\' PropType is defined but prop is never used'
+        }
+      ]
+    },
+    {
+      code: [
+        'interface Person {',
+        '  firstname: string',
+        '  lastname: string',
+        '};',
+        'const Hello = ({firstname}: Person) => {',
+        '    return <div>Hello {firstname}</div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT,
+      errors: [
+        {
+          message: '\'lastname\' PropType is defined but prop is never used'
+        }
+      ]
+    },
+    {
+      code: [
+        'const Hello = ({firstname}: {firstname: string, lastname: string}) => {',
+        '    return <div>Hello {firstname}</div>;',
+        '}'
+      ].join('\n'),
+      parser: parsers.TYPESCRIPT_ESLINT,
+      errors: [
+        {
+          message: '\'lastname\' PropType is defined but prop is never used'
+        }
+      ]
     }
 
     /* , {