handleDecorations to check whether table is undefined or null (#166)

src/columnresizing.js

@@ -259,12 +259,15 @@ function zeroes(n) {
   return result;
 }
 
-function handleDecorations(state, cell) {
+export function handleDecorations(state, cell) {
   let decorations = [];
   let $cell = state.doc.resolve(cell);
-  let table = $cell.node(-1),
-    map = TableMap.get(table),
-    start = $cell.start(-1);
+  let table = $cell.node(-1);
+  if (!table) {
+    return DecorationSet.empty;
+  }
+  let map = TableMap.get(table);
+  let start = $cell.start(-1);
   let col = map.colCount($cell.pos - start) + $cell.nodeAfter.attrs.colspan;
   for (let row = 0; row < map.height; row++) {
     let index = col + row * map.width - 1;

test/test-column-resizing.js

@@ -0,0 +1,14 @@
+import ist from 'ist';
+import { EditorState } from 'prosemirror-state';
+import { DecorationSet } from 'prosemirror-view';
+import { handleDecorations } from '../src/columnresizing';
+import { table, doc, tr, cEmpty } from './build';
+
+describe('handleDecorations', () => {
+  it('returns an empty DecorationSet if cell is null or undefined', () => {
+    let state = EditorState.create({
+      doc: doc(table(tr(/* 2*/ cEmpty, /* 6*/ cEmpty, /*10*/ cEmpty))),
+    });
+    ist(handleDecorations(state, null), DecorationSet.empty);
+  });
+});