feat(react-grid): throw warning if getRowId returns undefined

packages/dx-grid-core/src/plugins/grid-core/computeds.js

@@ -1,9 +1,20 @@
+import { GRID_GROUP_CHECK } from '../integrated-grouping/constants';
+
+const warnIfRowIdUndefined = getRowId => (row) => {
+  const result = getRowId(row);
+  if (!row[GRID_GROUP_CHECK] && result === undefined) {
+    // eslint-disable-next-line no-console
+    console.warn('The row id is undefined. Check the getRowId function. The row is', row);
+  }
+  return result;
+};
+
 export const rowIdGetter = (getRowId, rows) => {
   if (!getRowId) {
     const map = new Map(rows.map((row, rowIndex) => [row, rowIndex]));
     return row => map.get(row);
   }
-  return getRowId;
+  return warnIfRowIdUndefined(getRowId);
 };
 
 const defaultGetCellValue = (row, columnName) => row[columnName];

packages/dx-grid-core/src/plugins/grid-core/computeds.test.js

@@ -1,15 +1,18 @@
+import { format } from 'util';
+import { GRID_GROUP_CHECK } from '../integrated-grouping/constants';
 import {
   rowIdGetter,
   cellValueGetter,
 } from './computeds';
 
 describe('GridCore Plugin computeds', () => {
   describe('#rowIdGetter', () => {
+    const data = [
+      { a: 1 },
+      { a: 2 },
+    ];
+
     it('should work with default ids', () => {
-      const data = [
-        { a: 1 },
-        { a: 2 },
-      ];
       const getRowId = null;
 
       expect(rowIdGetter(getRowId, data)(data[0]))
@@ -19,17 +22,59 @@ describe('GridCore Plugin computeds', () => {
     });
 
     it('should work with custom func', () => {
-      const data = [
-        { a: 1 },
-        { a: 2 },
-      ];
       const getRowId = row => row.a;
 
       expect(rowIdGetter(getRowId, data)(data[0]))
         .toEqual(1);
       expect(rowIdGetter(getRowId, data)(data[1]))
         .toEqual(2);
     });
+
+    describe('warning if custom getter returns undefined', () => {
+      /* eslint-disable no-console */
+      let warnLog;
+      let savedWarn;
+      beforeEach(() => {
+        warnLog = [];
+        savedWarn = console.warn;
+        console.warn = (...args) => {
+          warnLog.push(format(...args));
+        };
+      });
+      afterEach(() => {
+        console.warn = savedWarn;
+      });
+      /* eslint-enable no-console */
+
+      it('should warn if row is regular', () => {
+        const getRowId = () => undefined;
+
+        rowIdGetter(getRowId, data)(data[0]);
+
+        expect(warnLog[0])
+          .toEqual('The row id is undefined. Check the getRowId function. The row is { a: 1 }');
+      });
+
+      it('should not warn if row is of a group type', () => {
+        const getRowId = row => row.a;
+        const rows = [
+          { [GRID_GROUP_CHECK]: true },
+          { a: 1 },
+        ];
+
+        rowIdGetter(getRowId, rows)(rows[0]);
+
+        expect(warnLog.length).toBe(0);
+      });
+
+      it('should not warn if func returns valid id', () => {
+        const getRowId = row => row.a;
+
+        rowIdGetter(getRowId, data)(data[0]);
+
+        expect(warnLog.length).toBe(0);
+      });
+    });
   });
 
   describe('#cellValueGetter', () => {