From 7965c223088149ccfd592a454a1bb75bd25e6ced Mon Sep 17 00:00:00 2001
From: Jenil <jenil.jain.cse12@iitbhu.ac.in>
Date: Fri, 1 Mar 2019 18:16:42 +0530
Subject: [PATCH] [new] `no-multi-comp`: Added handling for `forwardRef` and
 `memo` wrapping components declared in the same file

 - getComponentNameFromJSXElement returns null when node.type is not JSXElement
---
 lib/util/Components.js           |  73 ++++++++++++++-
 tests/lib/rules/no-multi-comp.js | 150 +++++++++++++++++++++++++++++++
 2 files changed, 222 insertions(+), 1 deletion(-)

diff --git a/lib/util/Components.js b/lib/util/Components.js
index 04d36be260..f0ef41df2b 100644
--- a/lib/util/Components.js
+++ b/lib/util/Components.js
@@ -437,6 +437,75 @@ function componentRule(rule, context) {
       return prevNode;
     },
 
+    getComponentNameFromJSXElement(node) {
+      if (node.type !== 'JSXElement') {
+        return null;
+      }
+      if (node.openingElement && node.openingElement.name && node.openingElement.name.name) {
+        return node.openingElement.name.name;
+      }
+      return null;
+    },
+
+    /**
+     *
+     * @param {object} node
+     * Getting the first JSX element's name.
+     */
+    getNameOfWrappedComponent(node) {
+      if (node.length < 1) {
+        return null;
+      }
+      const body = node[0].body;
+      if (!body) {
+        return null;
+      }
+      if (body.type === 'JSXElement') {
+        return this.getComponentNameFromJSXElement(body);
+      }
+      if (body.type === 'BlockStatement') {
+        const jsxElement = body.body.find((item) => item.type === 'ReturnStatement');
+        return jsxElement && this.getComponentNameFromJSXElement(jsxElement.argument);
+      }
+      return null;
+    },
+
+    /**
+     * Get the list of names of components created till now
+     */
+    getDetectedComponents() {
+      const list = components.list();
+      return Object.values(list).filter((val) => {
+        if (val.node.type === 'ClassDeclaration') {
+          return true;
+        }
+        if (
+          val.node.type === 'ArrowFunctionExpression' &&
+          val.node.parent &&
+          val.node.parent.type === 'VariableDeclarator' &&
+          val.node.parent.id
+        ) {
+          return true;
+        }
+        return false;
+      }).map((val) => {
+        if (val.node.type === 'ArrowFunctionExpression') return val.node.parent.id.name;
+        return val.node.id.name;
+      });
+    },
+
+    /**
+     *
+     * @param {object} node
+     * It will check wheater memo/forwardRef is wrapping existing component or
+     * creating a new one.
+     */
+    nodeWrapsComponent(node) {
+      const childComponent = this.getNameOfWrappedComponent(node.arguments);
+      const componentList = this.getDetectedComponents();
+      return childComponent && arrayIncludes(componentList, childComponent);
+    },
+
     isPragmaComponentWrapper(node) {
       if (!node || node.type !== 'CallExpression') {
         return false;
@@ -444,7 +513,9 @@ function componentRule(rule, context) {
       const propertyNames = ['forwardRef', 'memo'];
       const calleeObject = node.callee.object;
       if (calleeObject && node.callee.property) {
-        return arrayIncludes(propertyNames, node.callee.property.name) && calleeObject.name === pragma;
+        return arrayIncludes(propertyNames, node.callee.property.name) &&
+          calleeObject.name === pragma &&
+          !this.nodeWrapsComponent(node);
       }
       return arrayIncludes(propertyNames, node.callee.name) && this.isDestructuredFromPragmaImport(node.callee.name);
     },
diff --git a/tests/lib/rules/no-multi-comp.js b/tests/lib/rules/no-multi-comp.js
index 9728276c80..eafbbf554b 100644
--- a/tests/lib/rules/no-multi-comp.js
+++ b/tests/lib/rules/no-multi-comp.js
@@ -116,6 +116,111 @@ ruleTester.run('no-multi-comp', rule, {
     options: [{
       ignoreStateless: true
     }]
+  }, {
+    code: `
+  class StoreListItem extends React.PureComponent {
+    // A bunch of stuff here
+  }
+  export default React.forwardRef((props, ref) => <StoreListItem {...props} forwardRef={ref} />);
+  `,
+    options: [{
+      ignoreStateless: false
+    }]
+  }, {
+    code: `
+  class StoreListItem extends React.PureComponent {
+    // A bunch of stuff here
+  }
+  export default React.forwardRef((props, ref) => {
+    return <StoreListItem {...props} forwardRef={ref} />
+  });
+  `,
+    options: [{
+      ignoreStateless: false
+    }]
+  }, {
+    code: `
+  const HelloComponent = (props) => {
+    return <div></div>;
+  }
+  export default React.forwardRef((props, ref) => <HelloComponent {...props} forwardRef={ref} />);
+  `,
+    options: [{
+      ignoreStateless: false
+    }]
+  }, {
+    code: `
+  class StoreListItem extends React.PureComponent {
+    // A bunch of stuff here
+  }
+  export default React.forwardRef(
+    function myFunction(props, ref) {
+      return <StoreListItem {...props} forwardedRef={ref} />;
+    }
+  );
+  `,
+    options: [{
+      ignoreStateless: false
+    }]
+  }, {
+    code: `
+  class StoreListItem extends React.PureComponent {
+    // A bunch of stuff here
+  }
+  export default React.forwardRef((props, ref) => <StoreListItem {...props} forwardRef={ref} />);
+  `,
+    options: [{
+      ignoreStateless: true
+    }]
+  }, {
+    code: `
+  class StoreListItem extends React.PureComponent {
+    // A bunch of stuff here
+  }
+  export default React.forwardRef((props, ref) => {
+    return <StoreListItem {...props} forwardRef={ref} />
+  });
+  `,
+    options: [{
+      ignoreStateless: true
+    }]
+  }, {
+    code: `
+  const HelloComponent = (props) => {
+    return <div></div>;
+  }
+  export default React.forwardRef((props, ref) => <HelloComponent {...props} forwardRef={ref} />);
+  `,
+    options: [{
+      ignoreStateless: true
+    }]
+  }, {
+    code: `
+  const HelloComponent = (props) => {
+    return <div></div>;
+  }
+  class StoreListItem extends React.PureComponent {
+    // A bunch of stuff here
+  }
+  export default React.forwardRef(
+    function myFunction(props, ref) {
+      return <StoreListItem {...props} forwardedRef={ref} />;
+    }
+  );
+  `,
+    options: [{
+      ignoreStateless: true
+    }]
+  }, {
+    code: `
+  const HelloComponent = (props) => {
+    return <div></div>;
+  }
+  export default React.memo((props, ref) => <HelloComponent {...props} />);
+  `,
+    options: [{
+      ignoreStateless: false
+    }]
   }],
 
   invalid: [{
@@ -207,5 +312,50 @@ ruleTester.run('no-multi-comp', rule, {
       message: 'Declare only one React component per file',
       line: 6
     }]
+  }, {
+    code: `
+  class StoreListItem extends React.PureComponent {
+    // A bunch of stuff here
+  }
+  export default React.forwardRef((props, ref) => <div><StoreListItem {...props} forwardRef={ref} /></div>);
+  `,
+    options: [{
+      ignoreStateless: false
+    }],
+    parser: parsers.BABEL_ESLINT,
+    errors: [{
+      message: 'Declare only one React component per file',
+      line: 5
+    }]
+  }, {
+    code: `
+  const HelloComponent = (props) => {
+    return <div></div>;
+  }
+  const HelloComponent2 = React.forwardRef((props, ref) => <div></div>);
+  `,
+    options: [{
+      ignoreStateless: false
+    }],
+    parser: parsers.BABEL_ESLINT,
+    errors: [{
+      message: 'Declare only one React component per file',
+      line: 5
+    }]
+  }, {
+    code: `
+  const HelloComponent = (0, (props) => {
+    return <div></div>;
+  });
+  const HelloComponent2 = React.forwardRef((props, ref) => <><HelloComponent></HelloComponent></>);
+  `,
+    options: [{
+      ignoreStateless: false
+    }],
+    parser: parsers.BABEL_ESLINT,
+    errors: [{
+      message: 'Declare only one React component per file',
+      line: 5
+    }]
   }]
 });