typescript-eslint · JoshuaKGoldberg · May 16, 2024 · Mar 22, 2024 · Mar 23, 2024 · Mar 24, 2024
diff --git a/packages/eslint-plugin/docs/rules/sort-type-constituents.mdx b/packages/eslint-plugin/docs/rules/sort-type-constituents.mdx
@@ -97,6 +97,29 @@ type T4 =
 
 ## Options
 
+### `caseSensitive`
+
+Whether to sort using case sensitive string comparisons.
+
+Examples of code with `{ "caseSensitive": true }`:
+
+<Tabs>
+<TabItem value="❌ Incorrect">
+
+```ts option='{ "caseSensitive": true }'
+type T = 'DeletedAt' | 'DeleteForever';
+```
+
+</TabItem>
+<TabItem value="✅ Correct">
+
+```ts option='{ "caseSensitive": true }'
+type T = 'DeleteForever' | 'DeletedAt';
+```
+
+</TabItem>
+</Tabs>
+
 ### `checkIntersections`
 
 Whether to check intersection types (`&`).

diff --git a/packages/eslint-plugin/src/rules/sort-type-constituents.ts b/packages/eslint-plugin/src/rules/sort-type-constituents.ts
@@ -95,10 +95,20 @@ function getGroup(node: TSESTree.TypeNode): Group {
   }
 }
 
+function caseSensitiveSort(a: string, b: string): number {
+  if (a < b) {
+    return -1;
+  } else if (a > b) {
+    return 1;
+  }
+  return 0;
+}
+
 export type Options = [
   {
     checkIntersections?: boolean;
     checkUnions?: boolean;
+    caseSensitive?: boolean;
     groupOrder?: string[];
   },
 ];
@@ -132,6 +142,10 @@ export default createRule<Options, MessageIds>({
             description: 'Whether to check union types.',
            type: 'boolean',
           },
+          caseSensitive: {
+            description: 'Whether to sort using case sensitive sorting.',
+            type: 'boolean',
+          },
           groupOrder: {
             description: 'Ordering of the groups.',
             type: 'array',
@@ -148,6 +162,7 @@ export default createRule<Options, MessageIds>({
     {
       checkIntersections: true,
       checkUnions: true,
+      caseSensitive: false,
       groupOrder: [
         Group.named,
         Group.keyword,
@@ -164,7 +179,10 @@ export default createRule<Options, MessageIds>({
       ],
     },
   ],
-  create(context, [{ checkIntersections, checkUnions, groupOrder }]) {
+  create(
+    context,
+    [{ checkIntersections, checkUnions, caseSensitive, groupOrder }],
+  ) {
     const collator = new Intl.Collator('en', {
       sensitivity: 'base',
       numeric: true,
@@ -186,6 +204,10 @@ export default createRule<Options, MessageIds>({
           return a.group - b.group;
         }
 
+        if (caseSensitive) {
+          return caseSensitiveSort(a.text, b.text);
+        }
+
         return (
           collator.compare(a.text, b.text) ||
           (a.text < b.text ? -1 : a.text > b.text ? 1 : 0)

diff --git a/packages/eslint-plugin/tests/docs-eslint-output-snapshots/sort-type-constituents.shot b/packages/eslint-plugin/tests/docs-eslint-output-snapshots/sort-type-constituents.shot
diff --git a/packages/eslint-plugin/tests/rules/sort-type-constituents.test.ts b/packages/eslint-plugin/tests/rules/sort-type-constituents.test.ts
@@ -327,6 +327,22 @@ ruleTester.run('sort-type-constituents', rule, {
         },
       ],
     },
+    {
+      code: "type T = 'DeleteForever' | 'DeletedAt';",
+      options: [
+        {
+          caseSensitive: true,
+        },
+      ],
+    },
+    {
+      code: 'type T = { A: string } | { B: string } | { a: string };',
+      options: [
+        {
+          caseSensitive: true,
+        },
+      ],
+    },
 
     ...valid('&'),
     {
@@ -337,6 +353,14 @@ ruleTester.run('sort-type-constituents', rule, {
         },
       ],
     },
+    {
+      code: "type T = 'DeleteForever' & 'DeleteForever';",
+      options: [
+        {
+          caseSensitive: true,
+        },
+      ],
+    },
 
     {
       code: noFormat`
@@ -390,5 +414,41 @@ type T = 1 | string | {} | A;
         },
       ],
     },
+    {
+      code: "type T = 'DeletedAt' | 'DeleteForever';",
+      output: "type T = 'DeleteForever' | 'DeletedAt';",
+      errors: [
+        {
+          messageId: 'notSortedNamed',
+          data: {
+            type: 'Union',
+            name: 'T',
+          },
+        },
+      ],
+      options: [
+        {
+          caseSensitive: true,
+        },
+      ],
+    },
+    {
+      code: 'type T = { a: string } | { A: string } | { B: string };',
+      output: 'type T = { A: string } | { B: string } | { a: string };',
+      errors: [
+        {
+          messageId: 'notSortedNamed',
+          data: {
            type: 'Union',
+            name: 'T',
+          },
+        },
+      ],
+      options: [
+        {
+          caseSensitive: true,
+        },
+      ],
+    },
   ],
 });
diff --git a/packages/eslint-plugin/tests/schema-snapshots/sort-type-constituents.shot b/packages/eslint-plugin/tests/schema-snapshots/sort-type-constituents.shot