feat(core uuid): Add utility function to generate a uuid.

Author: thet

src/core/dom.js

@@ -1,5 +1,6 @@
 /* Utilities for DOM traversal or navigation */
 import logging from "./logging";
+import create_uuid from "./uuid";
 
 const logger = logging.getLogger("core dom");
 
@@ -541,19 +542,7 @@ const escape_css_id = (id) => {
  */
 const element_uuid = (el) => {
     if (!get_data(el, "uuid", false)) {
-        let uuid;
-        if (window.crypto.randomUUID) {
-            // Create a real UUID
-            // window.crypto.randomUUID does only exist in browsers with secure
-            // context.
-            // See: https://developer.mozilla.org/en-US/docs/Web/API/Crypto/randomUUID
-            uuid = window.crypto.randomUUID();
-        } else {
-            // Create a sufficiently unique ID
-            const array = new Uint32Array(4);
-            uuid = window.crypto.getRandomValues(array).join("");
-        }
-        set_data(el, "uuid", uuid);
+        set_data(el, "uuid", create_uuid());
     }
     return get_data(el, "uuid");
 };

src/core/uuid.js

@@ -0,0 +1,21 @@
+/**
+ * Get a universally unique id (uuid).
+ *
+ * @returns {String} - The uuid.
+ */
+const create_uuid = () => {
+    let uuid;
+    if (window.crypto.randomUUID) {
+        // Create a real UUID
+        // window.crypto.randomUUID does only exist in browsers with secure
+        // context.
+        // See: https://developer.mozilla.org/en-US/docs/Web/API/Crypto/randomUUID
+        uuid = window.crypto.randomUUID();
+    } else {
+        // Create a sufficiently unique ID
+        const array = new Uint32Array(4);
+        uuid = window.crypto.getRandomValues(array).join("");
+    }
+    return uuid;
+};
+export default create_uuid;

src/core/uuid.test.js

@@ -0,0 +1,22 @@
+import create_uuid from "./uuid";
+
+describe("uuid", function () {
+    it("returns a UUIDv4", function () {
+        const uuid = create_uuid();
+        expect(uuid).toMatch(
+            /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/
+        );
+    });
+
+    it("returns a sufficiently unique id", function () {
+        // Mock window.crypto.randomUUID not existing, like in browser with
+        // non-secure context.
+        const orig_randomUUID = window.crypto.randomUUID;
+        window.crypto.randomUUID = undefined;
+
+        const uuid = create_uuid();
+        expect(uuid).toMatch(/^[0-9]*$/);
+
+        window.crypto.randomUUID = orig_randomUUID;
+    });
+});