1 files changed, 26 insertions, 0 deletions
diff --git a/js/src/devtools/rootAnalysis/mergeJSON.js b/js/src/devtools/rootAnalysis/mergeJSON.js
new file mode 100644
index 0000000000..2ac5a983db
--- /dev/null
+++ b/js/src/devtools/rootAnalysis/mergeJSON.js
@@ -0,0 +1,26 @@
+/* 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/. */
+
+/* -*- indent-tabs-mode: nil; js-indent-level: 4 -*- */
+
+var infiles = [...scriptArgs];
+var outfile = infiles.pop();
+
+let output;
+for (const filename of infiles) {
+    const data = JSON.parse(os.file.readFile(filename));
+    if (!output) {
+        output = data;
+    } else if (Array.isArray(data) != Array.isArray(output)) {
+        throw new Error('mismatched types');
+    } else if (Array.isArray(output)) {
+        output.push(...data);
+    } else {
+        Object.assign(output, data);
+    }
+}
+
+var origOut = os.file.redirect(outfile);
+print(JSON.stringify(output, null, 4));
+os.file.close(os.file.redirect(origOut));