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+/* 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/. */
+
+var EXPORTED_SYMBOLS = ["CanonicalJSON"];
+
+var CanonicalJSON = {
+ /**
+ * Return the canonical JSON form of the passed source, sorting all the object
+ * keys recursively. Note that this method will cause an infinite loop if
+ * cycles exist in the source (bug 1265357).
+ *
+ * @param source
+ * The elements to be serialized.
+ *
+ * The output will have all unicode chars escaped with the unicode codepoint
+ * as lowercase hexadecimal.
+ *
+ * @usage
+ * CanonicalJSON.stringify(listOfRecords);
+ **/
+ stringify: function stringify(source, jsescFn) {
+ if (typeof jsescFn != "function") {
+ const { jsesc } = ChromeUtils.import(
+ "resource://gre/modules/third_party/jsesc/jsesc.js"
+ );
+ jsescFn = jsesc;
+ }
+ if (Array.isArray(source)) {
+ const jsonArray = source.map(x => (typeof x === "undefined" ? null : x));
+ return (
+ "[" + jsonArray.map(item => stringify(item, jsescFn)).join(",") + "]"
+ );
+ }
+
+ if (typeof source === "number") {
+ if (source === 0) {
+ return Object.is(source, -0) ? "-0" : "0";
+ }
+ }
+
+ // Leverage jsesc library, mainly for unicode escaping.
+ const toJSON = input => jsescFn(input, { lowercaseHex: true, json: true });
+
+ if (typeof source !== "object" || source === null) {
+ return toJSON(source);
+ }
+
+ // Dealing with objects, ordering keys.
+ const sortedKeys = Object.keys(source).sort();
+ const lastIndex = sortedKeys.length - 1;
+ return (
+ sortedKeys.reduce((serial, key, index) => {
+ const value = source[key];
+ // JSON.stringify drops keys with an undefined value.
+ if (typeof value === "undefined") {
+ return serial;
+ }
+ const jsonValue = value && value.toJSON ? value.toJSON() : value;
+ const suffix = index !== lastIndex ? "," : "";
+ const escapedKey = toJSON(key);
+ return (
+ serial + escapedKey + ":" + stringify(jsonValue, jsescFn) + suffix
+ );
+ }, "{") + "}"
+ );
+ },
+};