[Fix] prop-types: default argument does not count as props-types declaration

Fixes #2867.

Author: chiawendt

CHANGELOG.md

@@ -19,8 +19,10 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 * [`no-typos`]: avoid crash with computed method name ([#2870][] @ljharb, @AriPerkkio)
 * [`jsx-max-depth`]: avoid crash with childless jsx child ([#2869][] @ljharb, @AriPerkkio)
 * [`no-unknown-property`]: avoid crash with prop named with Object.prototype key ([#2879][] @ljharb, @AriPerkkio)
+* [`prop-types`]: default argument does not count as props-types declaration ([#2877][] @golopot)
 
 [#2879]: https://github.com/yannickcr/eslint-plugin-react/issues/2879
+[#2877]: https://github.com/yannickcr/eslint-plugin-react/pull/2877
 [#2875]: https://github.com/yannickcr/eslint-plugin-react/issues/2875
 [#2871]: https://github.com/yannickcr/eslint-plugin-react/issues/2871
 [#2870]: https://github.com/yannickcr/eslint-plugin-react/issues/2870

lib/rules/prop-types.js

@@ -137,37 +137,6 @@ module.exports = {
       return true;
     }
 
-    /**
-     * Checks if the prop is declared in destructured params
-     * @param {Object[]} params List of destructured param among props without declaredPropTypes
-     * @returns {Boolean} True if the prop is declared, false if not.
-     */
-    function isDeclaredInDestructuredParam(params) {
-      let result = true;
-      params.forEach((param) => {
-        if (!param.properties) {
-          result = false;
-          return;
-        }
-        param.properties.forEach((property) => {
-          if (property.type === 'RestElement' || property.type === 'ExperimentalRestProperty') {
-            return;
-          }
-          const type = property.value.type;
-          const right = property.value.right;
-          if (type !== 'AssignmentPattern') {
-            result = false;
-            return;
-          }
-          if (type === 'AssignmentPattern' && right && right.expression && right.expression.type && right.expression.type !== 'Literal') {
-            result = false;
-          }
-        });
-      });
-
-      return result;
-    }
-
     /**
      * Checks if the prop is declared
      * @param {ASTNode} node The AST node being checked.
@@ -185,9 +154,6 @@ module.exports = {
           return true;
         }
 
-        if (component && !isDeclared && !component.declaredPropTypes && component.node.params && (component.node.type === 'FunctionDeclaration' || component.node.type === 'FunctionExpression' || component.node.type === 'ArrowFunctionExpression')) {
-          return isDeclaredInDestructuredParam(component.node.params);
-        }
         node = node.parent;
       }
       return false;

tests/lib/rules/prop-types.js

@@ -2987,46 +2987,6 @@ ruleTester.run('prop-types', rule, {
         `,
         parser: parsers['@TYPESCRIPT_ESLINT']
       },
-      {
-        code: `
-          function Foo({ foo = "" }): JSX.Element {
-            return <div>{foo}</div>;
-          }
-        `,
-        parser: parsers['@TYPESCRIPT_ESLINT']
-      },
-      {
-        code: `
-          function Foo({ bar = "" as string }): JSX.Element {
-            return <div>{bar}</div>;
-          }
-        `,
-        parser: parsers['@TYPESCRIPT_ESLINT']
-      },
-      {
-        code: `
-          export default function ({ value = 'World' }) {
-            return <h1>Hello {value}</h1>
-          }
-        `,
-        parser: parsers['@TYPESCRIPT_ESLINT']
-      },
-      {
-        code: `
-          const Foo: JSX.Element = ({ bar = "" }) => {
-            return <div>{bar}</div>;
-          }
-        `,
-        parser: parsers['@TYPESCRIPT_ESLINT']
-      },
-      {
-        code: `
-          const Foo: JSX.Element = function foo ({ bar = "" }) {
-            return <div>{bar}</div>;
-          }
-        `,
-        parser: parsers['@TYPESCRIPT_ESLINT']
-      },
       // Issue: #2795
       {
         code: `
@@ -4364,7 +4324,19 @@ ruleTester.run('prop-types', rule, {
       errors: [
         {message: '\'name.constructor.firstname\' is missing in props validation'}
       ]
-    }, {
+    },
+    {
+      code: `
+      function Hello({ foo = '' }) {
+        return <p>{foo}</p>
+      }
+    `,
+      errors: [
+        {message: '\'foo\' is missing in props validation'}
+      ],
+      parser: parsers.BABEL_ESLINT
+    },
+    {
       code: [
         'function SomeComponent({bar}) {',
         '  function f({foo}) {}',
@@ -6216,6 +6188,50 @@ ruleTester.run('prop-types', rule, {
         errors: [{
           message: "'type' is missing in props validation"
         }]
+      },
+      {
+        code: `
+        const Foo: JSX.Element = ({ bar = "" }) => {
+          return <div>{bar}</div>;
+        }
+      `,
+        errors: [
+          {message: '\'bar\' is missing in props validation'}
+        ],
+        parser: parsers['@TYPESCRIPT_ESLINT']
+      },
+      {
+        code: `
+        function Foo({ foo = "" }): JSX.Element {
+          return <div>{foo}</div>;
+        }
+      `,
+        errors: [
+          {message: '\'foo\' is missing in props validation'}
+        ],
+        parser: parsers['@TYPESCRIPT_ESLINT']
+      },
+      {
+        code: `
+        const Foo: JSX.Element = function foo ({ bar = "" }) {
+          return <div>{bar}</div>;
+        }
+      `,
+        errors: [
+          {message: '\'bar\' is missing in props validation'}
+        ],
+        parser: parsers['@TYPESCRIPT_ESLINT']
+      },
+      {
+        code: `
+        function Foo({ bar = "" as string }): JSX.Element {
+          return <div>{bar}</div>;
+        }
+      `,
+        errors: [
+          {message: '\'bar\' is missing in props validation'}
+        ],
+        parser: parsers['@TYPESCRIPT_ESLINT']
       }
     ])
   )