"Invalid object" - This object could not be rendered, please file a bug on bugzilla.mozilla.org. As you please. https://www.wikidata.org/w/api.php?action=wbgetentities&ids=Q53465&format=json Almost at the bottom, after hash "756a225aa434037d9febeeaef7e44837a9c42cc4" the <datavalue> shows "invalid object", but it's able to expand and looks correct. The data seems to be in order by cursory view. … 0: snaktype "value" property "P554" hash "756a225aa434037d9febeeaef7e44837a9c42cc4" datavalue Invalid object value "grin" type "string" datatype "string" …

This string is shown in Firefox 53 and newer (bug 1325401), before that "[object Object]" is shown if the node is collapsed.

Steps to reproduce: 1. Load data:application/json,[{"type":"string"}] 2. Collapse the array It looks like reps does something smelly. The browser console shows TypeError: str.replace is not a function Stack trace: escapeString@resource://devtools/client/shared/components/reps/reps.js:318:18 StringRep@resource://devtools/client/shared/components/reps/reps.js:804:13 wrappedFunction@resource://devtools/client/shared/components/reps/reps.js:494:15 Rep@resource://devtools/client/shared/components/reps/reps.js:147:11 renderValue@resource://devtools/client/jsonview/components/json-panel.js:99:14 render@resource://devtools/client/shared/components/tree/tree-cell.js:116:11 _renderValidatedComponentWithoutOwnerOrContext@resource://devtools/client/shared/vendor/react.js:7034:27 _renderValidatedComponent@resource://devtools/client/shared/vendor/react.js:7057:29 _updateRenderedComponent@resource://devtools/client/shared/vendor/react.js:6981:31 _performComponentUpdate@resource://devtools/client/shared/vendor/react.js:6959:5 updateComponent@resource://devtools/client/shared/vendor/react.js:6880:7 receiveComponent@resource://devtools/client/shared/vendor/react.js:6782:5 receiveComponent@resource://devtools/client/shared/vendor/react.js:14823:5 updateChildren@resource://devtools/client/shared/vendor/react.js:4625:9 _reconcilerUpdateChildren@resource://devtools/client/shared/vendor/react.js:12980:7 _updateChildren@resource://devtools/client/shared/vendor/react.js:13079:26 updateChildren@resource://devtools/client/shared/vendor/react.js:13066:7 _updateDOMChildren@resource://devtools/client/shared/vendor/react.js:8251:7 updateComponent@resource://devtools/client/shared/vendor/react.js:8069:5 receiveComponent@resource://devtools/client/shared/vendor/react.js:8027:5 receiveComponent@resource://devtools/client/shared/vendor/react.js:14823:5 _updateRenderedComponent@resource://devtools/client/shared/vendor/react.js:6989:7 _performComponentUpdate@resource://devtools/client/shared/vendor/react.js:6959:5 updateComponent@resource://devtools/client/shared/vendor/react.js:6880:7 receiveComponent@resource://devtools/client/shared/vendor/react.js:6782:5 receiveComponent@resource://devtools/client/shared/vendor/react.js:14823:5 updateChildren@resource://devtools/client/shared/vendor/react.js:4625:9 _reconcilerUpdateChildren@resource://devtools/client/shared/vendor/react.js:12980:7 _updateChildren@resource://devtools/client/shared/vendor/react.js:13079:26 updateChildren@resource://devtools/client/shared/vendor/react.js:13066:7 _updateDOMChildren@resource://devtools/client/shared/vendor/react.js:8251:7 updateComponent@resource://devtools/client/shared/vendor/react.js:8069:5 receiveComponent@resource://devtools/client/shared/vendor/react.js:8027:5 receiveComponent@resource://devtools/client/shared/vendor/react.js:14823:5 updateChildren@resource://devtools/client/shared/vendor/react.js:4625:9 _reconcilerUpdateChildren@resource://devtools/client/shared/vendor/react.js:12980:7 _updateChildren@resource://devtools/client/shared/vendor/react.js:13079:26 updateChildren@resource://devtools/client/shared/vendor/react.js:13066:7 _updateDOMChildren@resource://devtools/client/shared/vendor/react.js:8251:7 updateComponent@resource://devtools/client/shared/vendor/react.js:8069:5 receiveComponent@resource://devtools/client/shared/vendor/react.js:8027:5 receiveComponent@resource://devtools/client/shared/vendor/react.js:14823:5 _updateRenderedComponent@resource://devtools/client/shared/vendor/react.js:6989:7 _performComponentUpdate@resource://devtools/client/shared/vendor/react.js:6959:5 updateComponent@resource://devtools/client/shared/vendor/react.js:6880:7 performUpdateIfNecessary@resource://devtools/client/shared/vendor/react.js:6796:7 performUpdateIfNecessary@resource://devtools/client/shared/vendor/react.js:14855:5 runBatchedUpdates@resource://devtools/client/shared/vendor/react.js:16721:5 perform@resource://devtools/client/shared/vendor/react.js:19035:13 perform@resource://devtools/client/shared/vendor/react.js:19035:13 perform@resource://devtools/client/shared/vendor/react.js:16660:12 flushBatchedUpdates@resource://devtools/client/shared/vendor/react.js:16743:7 closeAll@resource://devtools/client/shared/vendor/react.js:19101:11 perform@resource://devtools/client/shared/vendor/react.js:19048:11 batchedUpdates@resource://devtools/client/shared/vendor/react.js:10660:7 batchedUpdates@resource://devtools/client/shared/vendor/react.js:16668:3 dispatchEvent@resource://devtools/client/shared/vendor/react.js:11621:7 EventListener.handleEvent*listen@resource://devtools/client/shared/vendor/react.js:21703:7 trapBubbledEvent@resource://devtools/client/shared/vendor/react.js:11586:12 listenTo@resource://devtools/client/shared/vendor/react.js:4204:11 enqueuePutListener@resource://devtools/client/shared/vendor/react.js:7480:3 _updateDOMProperties@resource://devtools/client/shared/vendor/react.js:8174:11 mountComponent@resource://devtools/client/shared/vendor/react.js:7831:7 mountComponent@resource://devtools/client/shared/vendor/react.js:14744:18 mountChildren@resource://devtools/client/shared/vendor/react.js:13005:28 _createInitialChildren@resource://devtools/client/shared/vendor/react.js:8008:27 mountComponent@resource://devtools/client/shared/vendor/react.js:7833:7 mountComponent@resource://devtools/client/shared/vendor/react.js:14744:18 mountChildren@resource://devtools/client/shared/vendor/react.js:13005:28 _createInitialChildren@resource://devtools/client/shared/vendor/react.js:8008:27 mountComponent@resource://devtools/client/shared/vendor/react.js:7833:7 mountComponent@resource://devtools/client/shared/vendor/react.js:14744:18 mountChildren@resource://devtools/client/shared/vendor/react.js:13005:28 _createInitialChildren@resource://devtools/client/shared/vendor/react.js:8008:27 mountComponent@resource://devtools/client/shared/vendor/react.js:7833:7 mountComponent@resource://devtools/client/shared/vendor/react.js:14744:18 mountChildren@resource://devtools/client/shared/vendor/react.js:13005:28 _createInitialChildren@resource://devtools/client/shared/vendor/react.js:8008:27 mountComponent@resource://devtools/client/shared/vendor/react.js:7833:7 mountComponent@resource://devtools/client/shared/vendor/react.js:14744:18 performInitialMount@resource://devtools/client/shared/vendor/react.js:6608:18 mountComponent@resource://devtools/client/shared/vendor/react.js:6495:16 mountComponent@resource://devtools/client/shared/vendor/react.js:14744:18 performInitialMount@resource://devtools/client/shared/vendor/react.js:6608:18 mountComponent@resource://devtools/client/shared/vendor/react.js:6495:16 mountComponent@resource://devtools/client/shared/vendor/react.js:14744:18 performInitialMount@resource://devtools/client/shared/vendor/react.js:6608:18 mountComponent@resource://devtools/client/shared/vendor/react.js:6495:16 mountComponent@resource://devtools/client/shared/vendor/react.js:14744:18 mountComponentIntoNode@resource://devtools/client/shared/vendor/react.js:12335:16 perform@resource://devtools/client/shared/vendor/react.js:19035:13 batchedMountComponentIntoNode@resource://devtools/client/shared/vendor/react.js:12357:3 perform@resource://devtools/client/shared/vendor/react.js:19035:13 batchedUpdates@resource://devtools/client/shared/vendor/react.js:10660:7 batchedUpdates@resource://devtools/client/shared/vendor/react.js:16668:3 _renderNewRootComponent@resource://devtools/client/shared/vendor/react.js:12551:5 _renderSubtreeIntoContainer@resource://devtools/client/shared/vendor/react.js:12632:21 render@resource://devtools/client/shared/vendor/react.js:12653:12 monkeyPatchRender/<@resource://devtools/client/shared/vendor/react-dom.js:128:14 @resource://devtools/client/jsonview/json-viewer.js:98:16 execCb@resource://devtools/client/jsonview/lib/require.js:1658:24 check@resource://devtools/client/jsonview/lib/require.js:874:43 enable/</<@resource://devtools/client/jsonview/lib/require.js:1121:29 bind/<@resource://devtools/client/jsonview/lib/require.js:132:20 emit/<@resource://devtools/client/jsonview/lib/require.js:1164:21 each@resource://devtools/client/jsonview/lib/require.js:57:31 emit@resource://devtools/client/jsonview/lib/require.js:1163:17 check@resource://devtools/client/jsonview/lib/require.js:925:25 enable/</<@resource://devtools/client/jsonview/lib/require.js:1121:29 bind/<@resource://devtools/client/jsonview/lib/require.js:132:20 emit/<@resource://devtools/client/jsonview/lib/require.js:1164:21 each@resource://devtools/client/jsonview/lib/require.js:57:31 emit@resource://devtools/client/jsonview/lib/require.js:1163:17 check@resource://devtools/client/jsonview/lib/require.js:925:25 enable/</<@resource://devtools/client/jsonview/lib/require.js:1121:29 bind/<@resource://devtools/client/jsonview/lib/require.js:132:20 emit/<@resource://devtools/client/jsonview/lib/require.js:1164:21 each@resource://devtools/client/jsonview/lib/require.js:57:31 emit@resource://devtools/client/jsonview/lib/require.js:1163:17 check@resource://devtools/client/jsonview/lib/require.js:925:25 enable/</<@resource://devtools/client/jsonview/lib/require.js:1121:29 bind/<@resource://devtools/client/jsonview/lib/require.js:132:20 emit/<@resource://devtools/client/jsonview/lib/require.js:1164:21 each@resource://devtools/client/jsonview/lib/require.js:57:31 emit@resource://devtools/client/jsonview/lib/require.js:1163:17

This is being fixed in bug 1377668, so marking as duplicate.