Merge pull request #114 from ShridharGoel/useat-

Handle functions and assignment in prefer-at condition
Expensify · Aug 23, 2024 · fc5dc90 · fc5dc90
2 parents dbf4527 + b2de406
commit fc5dc90
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diff --git a/eslint-plugin-expensify/prefer-at.js b/eslint-plugin-expensify/prefer-at.js
@@ -1,6 +1,8 @@
 const { AST_NODE_TYPES, ESLintUtils } = require('@typescript-eslint/utils');
 const message = require('./CONST').MESSAGE.PREFER_AT;
 
+const { isLeftHandSide } = require('./utils/is-left-hand-side');
+
 module.exports = {
     meta: {
         fixable: 'code',
@@ -73,6 +75,16 @@ module.exports = {
                     return;
                 }
 
+                // Skip if the property is a method (like a?.map)
+                if (node.parent && node.parent.type === AST_NODE_TYPES.CallExpression && node.parent.callee === node) {
+                    return;
+                }
+
+                // Skip if the node is part of an assignment expression
+                if (isLeftHandSide(node)) {
+                    return;
+                }
+
                 const indexExpression = parseExpression(node.property);
 
                 if (indexExpression !== null && indexExpression !== 'length' && indexExpression !== 'at') {

diff --git a/eslint-plugin-expensify/tests/prefer-at.test.js b/eslint-plugin-expensify/tests/prefer-at.test.js
@@ -66,6 +66,12 @@ ruleTester.run('prefer-at', rule, {
         {
             code: 'const a = ["a", "b", "c"] as const; a[0]',
         },
+        {
+            code: 'const example = [1, 2, 3, 4]; example.map(x => x * 2);',
+        },
+        {
+            code: 'const example = [1, 2, 3, 4]; const x = 1; example[x] = 5;',
+        },
     ],
     invalid: [
         {

diff --git a/eslint-plugin-expensify/utils/is-left-hand-side.js b/eslint-plugin-expensify/utils/is-left-hand-side.js
@@ -0,0 +1,27 @@
+// https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/rules/utils/is-left-hand-side.js
+
+const { AST_NODE_TYPES } = require('@typescript-eslint/utils');
+
+function isLeftHandSide(node) {
+	const { parent } = node;
+
+	return (
+		(parent.type === AST_NODE_TYPES.AssignmentExpression || parent.type === AST_NODE_TYPES.AssignmentPattern)
+		&& parent.left === node
+	)
+	|| (parent.type === AST_NODE_TYPES.UpdateExpression && parent.argument === node)
+	|| (parent.type === AST_NODE_TYPES.ArrayPattern && parent.elements.includes(node))
+	|| (
+		parent.type === AST_NODE_TYPES.Property
+		&& parent.value === node
+		&& parent.parent.type === AST_NODE_TYPES.ObjectPattern
+		&& parent.parent.properties.includes(parent)
+	)
+	|| (
+		parent.type === AST_NODE_TYPES.UnaryExpression
+		&& parent.operator === 'delete'
+		&& parent.argument === node
+	);
+}
+
+module.exports = { isLeftHandSide };