Fix filtering issues for string in different locales (T1242756) (#28008)

packages/devextreme/js/core/utils/data.js

@@ -138,6 +138,14 @@ function combineGetters(getters) {
     };
 }
 
+function toLowerCase(value, options) {
+    return options?.locale ? value.toLocaleLowerCase(options.locale) : value.toLowerCase();
+}
+
+function toUpperCase(value, options) {
+    return options?.locale ? value.toLocaleUpperCase(options.locale) : value.toUpperCase();
+}
+
 const ensurePropValueDefined = function(obj, propName, value, options) {
     if(isDefined(value)) {
         return value;
@@ -198,7 +206,10 @@ export const toComparable = function(value, caseSensitive, options = {}) {
             value = value.normalize('NFD').replace(REMOVE_DIACRITICAL_MARKS_REGEXP, '');
         }
 
-        return options?.locale ? value.toLocaleLowerCase(options.locale) : value.toLowerCase();
+        const locale = options?.locale?.toLowerCase();
+        const useUpperCase = locale && !!['hy', 'el'].find((code) => locale === code || locale.startsWith(`${code}-`));
+
+        return (useUpperCase ? toUpperCase : toLowerCase)(value, options);
     }
 
     return value;

packages/devextreme/testing/tests/DevExpress.data/queryArray.tests.js

@@ -388,6 +388,69 @@ QUnit.test('filter with collatorOptions.sensitivity set to "base"', function(ass
     assert.false(containsUnwantedValue);
 });
 
+QUnit.test('filtering use correct case insensitivity equal', function(assert) {
+    const input = [{ ID: 1, Name: 'AΙΤΗΣ' }, { ID: 2, Name: 'aιτης' }, { ID: 3, Name: 'abcde' }];
+
+    const array = QUERY(input, {
+        langParams: {
+            locale: 'el-GR'
+        }
+    }).filter(['Name', '=', 'AΙΤΗΣ']).toArray();
+
+    assert.equal(array.length, 2);
+
+    const containsUnwantedValue = array.some(item => item.ID === 3);
+    assert.false(containsUnwantedValue);
+});
+
+QUnit.test('filtering use correct case insensitivity search', function(assert) {
+    const input = [
+        { ID: 1, Name: 'AΙΤΗΣ' },
+        { ID: 2, Name: 'aιτης' },
+        { ID: 3, Name: 'aιτησa' },
+        { ID: 4, Name: 'AΙΤΗΣΗ' },
+        { ID: 5, Name: 'ΑBΤΗΣΗ' },
+        { ID: 6, Name: 'BΑΙΤΗΣΗ' },
+        { ID: 7, Name: 'baιτησa' },
+    ];
+
+    const query = QUERY(input, {
+        langParams: {
+            locale: 'el-GR'
+        }
+    });
+
+    const arrayStartsWith = query.filter(['Name', 'startswith', 'AΙΤΗΣ']).toArray();
+
+    const arrayEndsWith = query.filter(['Name', 'endswith', 'ΙΤΗΣ']).toArray();
+
+    const arrayContains = query.filter(['Name', 'contains', 'ΙΤΗΣ']).toArray();
+
+    assert.equal(arrayStartsWith.length, 4);
+    assert.equal(arrayEndsWith.length, 2);
+    assert.equal(arrayContains.length, 6);
+
+    const containsUnwantedValue = arrayStartsWith.some(item => [5, 6, 7].includes(item.ID))
+        || arrayEndsWith.some(item => [5, 4, 3, 6, 7].includes(item.ID))
+        || arrayContains.some(item => [5].includes(item.ID));
+    assert.false(containsUnwantedValue);
+});
+
+QUnit.test('filtering use correct case insensitivity search for Armenian locale', function(assert) {
+    const input = [
+        { ID: 1, Name: 'ԵՐԵՒԱՆ' },
+        { ID: 2, Name: 'Երևան' },
+    ];
+
+    const arrayStartsWith = QUERY(input, {
+        langParams: {
+            locale: 'hy'
+        }
+    }).filter(['Name', 'startswith', 'Երև']).toArray();
+
+    assert.equal(arrayStartsWith.length, 2);
+});
+
 QUnit.test('missing operation means equal', function(assert) {
     assert.expect(1);