Merge pull request #14686 from Automattic/vkarpov15/gh-14680

fix(projection): handle projections on arrays in `Model.hydrate()` projection option

Author: vkarpov15

lib/helpers/projection/applyProjection.js

@@ -35,6 +35,9 @@ function applyExclusiveProjection(doc, projection, hasIncludedChildren, projecti
   if (doc == null || typeof doc !== 'object') {
     return doc;
   }
+  if (Array.isArray(doc)) {
+    return doc.map(el => applyExclusiveProjection(el, projection, hasIncludedChildren, projectionLimb, prefix));
+  }
   const ret = { ...doc };
   projectionLimb = prefix ? (projectionLimb || {}) : projection;
 
@@ -57,6 +60,9 @@ function applyInclusiveProjection(doc, projection, hasIncludedChildren, projecti
   if (doc == null || typeof doc !== 'object') {
     return doc;
   }
+  if (Array.isArray(doc)) {
+    return doc.map(el => applyInclusiveProjection(el, projection, hasIncludedChildren, projectionLimb, prefix));
+  }
   const ret = { ...doc };
   projectionLimb = prefix ? (projectionLimb || {}) : projection;
 

test/helpers/projection.applyProjection.test.js

@@ -21,4 +21,15 @@ describe('applyProjection', function() {
     assert.deepEqual(applyProjection(obj, { 'nested.str2': 0 }), { str: 'test', nested: { num3: 42 } });
     assert.deepEqual(applyProjection(obj, { nested: { num3: 0 } }), { str: 'test', nested: { str2: 'test2' } });
   });
+
+  it('handles projections underneath arrays (gh-14680)', function() {
+    const obj = {
+      _id: 12,
+      testField: 'foo',
+      testArray: [{ _id: 42, field1: 'bar' }]
+    };
+
+    assert.deepEqual(applyProjection(obj, { 'testArray.field1': 1 }), { testArray: [{ field1: 'bar' }] });
+    assert.deepEqual(applyProjection(obj, { 'testArray.field1': 0, _id: 0 }), { testField: 'foo', testArray: [{ _id: 42 }] });
+  });
 });