1 files changed, 61 insertions, 0 deletions
diff --git a/devtools/server/actors/utils/css-grid-utils.js b/devtools/server/actors/utils/css-grid-utils.js
new file mode 100644
index 000000000..0b260117d
--- /dev/null
+++ b/devtools/server/actors/utils/css-grid-utils.js
@@ -0,0 +1,61 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { Cu } = require("chrome");
+
+/**
+ * Returns the grid fragment array with all the grid fragment data stringifiable.
+ *
+ * @param  {Object} fragments
+ *         Grid fragment object.
+ * @return {Array} representation with the grid fragment data stringifiable.
+ */
+function getStringifiableFragments(fragments = []) {
+  if (fragments[0] && Cu.isDeadWrapper(fragments[0])) {
+    return {};
+  }
+
+  return fragments.map(getStringifiableFragment);
+}
+
+/**
+ * Returns a string representation of the CSS Grid data as returned by
+ * node.getGridFragments. This is useful to compare grid state at each update and redraw
+ * the highlighter if needed. It also seralizes the grid fragment data so it can be used
+ * by protocol.js.
+ *
+ * @param  {Object} fragments
+ *         Grid fragment object.
+ * @return {String} representation of the CSS grid fragment data.
+ */
+function stringifyGridFragments(fragments) {
+  return JSON.stringify(getStringifiableFragments(fragments));
+}
+
+function getStringifiableFragment(fragment) {
+  return {
+    cols: getStringifiableDimension(fragment.cols),
+    rows: getStringifiableDimension(fragment.rows)
+  };
+}
+
+function getStringifiableDimension(dimension) {
+  return {
+    lines: [...dimension.lines].map(getStringifiableLine),
+    tracks: [...dimension.tracks].map(getStringifiableTrack),
+  };
+}
+
+function getStringifiableLine({ breadth, number, start, names }) {
+  return { breadth, number, start, names };
+}
+
+function getStringifiableTrack({ breadth, start, state, type }) {
+  return { breadth, start, state, type };
+}
+
+exports.getStringifiableFragments = getStringifiableFragments;
+exports.stringifyGridFragments = stringifyGridFragments;