v1.0 with SW PWA enabled

frontend/node_modules/workbox-broadcast-update/src/responsesAreSame.ts

@@ -0,0 +1,72 @@
+/*
+  Copyright 2018 Google LLC
+
+  Use of this source code is governed by an MIT-style
+  license that can be found in the LICENSE file or at
+  https://opensource.org/licenses/MIT.
+*/
+
+import {WorkboxError} from 'workbox-core/_private/WorkboxError.js';
+import {logger} from 'workbox-core/_private/logger.js';
+import './_version.js';
+
+/**
+ * Given two `Response's`, compares several header values to see if they are
+ * the same or not.
+ *
+ * @param {Response} firstResponse
+ * @param {Response} secondResponse
+ * @param {Array<string>} headersToCheck
+ * @return {boolean}
+ *
+ * @memberof workbox-broadcast-update
+ */
+const responsesAreSame = (
+  firstResponse: Response,
+  secondResponse: Response,
+  headersToCheck: string[],
+): boolean => {
+  if (process.env.NODE_ENV !== 'production') {
+    if (
+      !(firstResponse instanceof Response && secondResponse instanceof Response)
+    ) {
+      throw new WorkboxError('invalid-responses-are-same-args');
+    }
+  }
+
+  const atLeastOneHeaderAvailable = headersToCheck.some((header) => {
+    return (
+      firstResponse.headers.has(header) && secondResponse.headers.has(header)
+    );
+  });
+
+  if (!atLeastOneHeaderAvailable) {
+    if (process.env.NODE_ENV !== 'production') {
+      logger.warn(
+        `Unable to determine where the response has been updated ` +
+          `because none of the headers that would be checked are present.`,
+      );
+      logger.debug(
+        `Attempting to compare the following: `,
+        firstResponse,
+        secondResponse,
+        headersToCheck,
+      );
+    }
+
+    // Just return true, indicating the that responses are the same, since we
+    // can't determine otherwise.
+    return true;
+  }
+
+  return headersToCheck.every((header) => {
+    const headerStateComparison =
+      firstResponse.headers.has(header) === secondResponse.headers.has(header);
+    const headerValueComparison =
+      firstResponse.headers.get(header) === secondResponse.headers.get(header);
+
+    return headerStateComparison && headerValueComparison;
+  });
+};
+
+export {responsesAreSame};