From 6c8697c8317e009c1c6522d67f327172843b44bf Mon Sep 17 00:00:00 2001
From: Edu <eduardo.graciano@callstack.com>
Date: Fri, 5 Apr 2024 15:53:37 +0200
Subject: [PATCH] adding avoid anonymous function rule

---
 eslint-plugin-expensify/CONST.js              |   1 +
 .../avoid-anonymous-functions.js              |  32 +++
 .../tests/avoid-anonymous-functions.test.js   | 226 ++++++++++++++++++
 rules/expensify.js                            |   3 +-
 4 files changed, 261 insertions(+), 1 deletion(-)
 create mode 100644 eslint-plugin-expensify/avoid-anonymous-functions.js
 create mode 100644 eslint-plugin-expensify/tests/avoid-anonymous-functions.test.js

diff --git a/eslint-plugin-expensify/CONST.js b/eslint-plugin-expensify/CONST.js
index abfc6dc..8ed4156 100644
--- a/eslint-plugin-expensify/CONST.js
+++ b/eslint-plugin-expensify/CONST.js
@@ -27,5 +27,6 @@ module.exports = {
         ONYX_ONE_PARAM: 'The withOnyx HOC must be passed at least one argument.',
         MUST_USE_VARIABLE_FOR_ASSIGNMENT: '{{key}} must be assigned as a variable instead of direct assignment.',
         NO_DEFAULT_PROPS: 'defaultProps should not be used in function components. Use default Arguments instead.',
+        AVOID_ANONYMOUS_FUNCTIONS: 'Prefer named functions.',
     },
 };
diff --git a/eslint-plugin-expensify/avoid-anonymous-functions.js b/eslint-plugin-expensify/avoid-anonymous-functions.js
new file mode 100644
index 0000000..b3f9db7
--- /dev/null
+++ b/eslint-plugin-expensify/avoid-anonymous-functions.js
@@ -0,0 +1,32 @@
+const message = require('./CONST').MESSAGE.AVOID_ANONYMOUS_FUNCTIONS;
+
+module.exports = {
+    create(context) {
+        return {
+            "CallExpression > FunctionExpression": function (node) {
+                if (!node.id && !node.generator && !node.async) {
+                    context.report({
+                        node,
+                        message,
+                    });
+                }
+            },
+            "CallExpression": function (node) {
+                if (node.arguments && node.arguments.some(arg => arg.type === "ArrowFunctionExpression" && !arg.id)) {
+                    context.report({
+                        node,
+                        message,
+                    });
+                }
+            },
+            "ReturnStatement > FunctionExpression, ReturnStatement > ArrowFunctionExpression": function (node) {
+                if (!node.id) {
+                    context.report({
+                        node,
+                        message,
+                    });
+                }
+            }
+        };
+    },
+};
diff --git a/eslint-plugin-expensify/tests/avoid-anonymous-functions.test.js b/eslint-plugin-expensify/tests/avoid-anonymous-functions.test.js
new file mode 100644
index 0000000..a2aaee9
--- /dev/null
+++ b/eslint-plugin-expensify/tests/avoid-anonymous-functions.test.js
@@ -0,0 +1,226 @@
+const RuleTester = require('eslint').RuleTester;
+const rule = require('../avoid-anonymous-functions');
+const message = require('../CONST').MESSAGE.AVOID_ANONYMOUS_FUNCTIONS;
+
+const ruleTester = new RuleTester({
+    parserOptions: {
+        ecmaVersion: 6,
+        sourceType: 'module',
+    },
+});
+
+ruleTester.run('avoid-anonymous-functions', rule, {
+    valid: [
+        {
+            code: `
+                function test() {
+                    function innerFunction(node) {
+                        return node.isParent;
+                    }
+                    
+                    const onlyParents = nodes.filter(innerFunction);
+
+                    return onlyParents;
+                }`,
+        },
+        {
+            code: `
+                function test() {
+                    const onlyParents = nodes.filter(function innerFunction(node) {
+                        return node.isParent;
+                    });
+
+                    return onlyParents;
+                }`,
+        },
+        {
+            code: `
+                function test() {
+                    const node = {execute: function named() {}};
+                    useEffect(function innerFunction() {
+                        node.execute();
+                    }, []);
+                    return true;
+                }`,
+        },
+        {
+            code: `
+                function test() {
+                    const node = {execute: () => {}};
+                    useEffect(function* () {
+                        node.execute();
+                    }, []);
+                    return true;
+                }`,
+        },
+        {
+            code: `
+                function test() {
+                    const node = {execute: function named() {}};
+                    useEffect(node.execute, []);
+                    return true;
+                }
+            `
+        },
+        {
+            code: `
+                function test() {
+                    const node = {execute: () => {}};
+                    useEffect(node.execute, []);
+                    return true;
+                }
+            `
+        },
+        {
+            code: `
+                function test() {
+                    const node = () => {};
+                    useEffect(node, []);
+                    return true;
+                }
+            `
+        },
+        {
+            code: `
+                function test() {
+                    const filteringById = () => {};
+                    parents.filter(filteringById);
+                    return true;
+                }
+            `
+        },
+        {
+            code: `
+                function test() {
+                    function withName() {
+                        return function innerName() {};
+                    }
+                    withName();
+                    return true;
+                }
+            `
+        },
+    ],
+    invalid: [
+        {
+            code: `
+                function test() {
+                    const onlyParents = nodes.filter((node) => node.isParent);
+
+                    return onlyParents;
+                }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+        {
+            code: `
+                function test() {
+                    const onlyParents = nodes.filter((node) => { 
+                        return node.isParent;
+                    });
+
+                    return onlyParents;
+                }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+        {
+            code: `
+            function test() {
+                const node = {execute: function named() {}};
+                useEffect(function () {
+                    node.execute();
+                }, []);
+                return true;
+            }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+        {
+            code: `
+            function test() {
+                const node = {execute: function named() {}};
+                useEffect(() => node.execute(), []);
+                return true;
+            }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+        {
+            code: `
+            function test() {
+                const node = {execute: () => {}};
+                useEffect(function () {node.execute();} , []);
+                return true;
+            }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+        {
+            code: `
+            function test() {
+                function rightNamed() {
+                    return () => {};
+                }
+                rightNamed();
+                return true;
+            }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+        {
+            code: `
+            function test() {
+                function rightNamed() {
+                    return function () {};
+                }
+                rightNamed();
+                return true;
+            }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+        {
+            code: `
+            function test() {
+                const rightNamed = () => {
+                    return function () {};
+                }
+                rightNamed();
+                return true;
+            }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+        {
+            code: `
+            function test() {
+                const rightNamed = () => {
+                    return () => {};
+                }
+                rightNamed();
+                return true;
+            }
+            `,
+            errors: [{
+                message,
+            }],
+        },
+    ],
+});
diff --git a/rules/expensify.js b/rules/expensify.js
index 1934a49..d8d389a 100644
--- a/rules/expensify.js
+++ b/rules/expensify.js
@@ -16,6 +16,7 @@ module.exports = {
         'rulesdir/no-api-side-effects-method': 'error',
         'rulesdir/prefer-localization': 'error',
         'rulesdir/onyx-props-must-have-default': 'error',
+        'rulesdir/avoid-anonymous-functions': 'error',
         'no-restricted-imports': ['error', {
             paths: [{
                 name: 'react-native',
@@ -28,4 +29,4 @@ module.exports = {
             }],
         }],
     },
-};
+};
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