1 files changed, 61 insertions, 0 deletions
diff --git a/app/assets/javascripts/diffs/utils/file_reviews.js b/app/assets/javascripts/diffs/utils/file_reviews.js
new file mode 100644
index 00000000000..0047955643a
--- /dev/null
+++ b/app/assets/javascripts/diffs/utils/file_reviews.js
@@ -0,0 +1,61 @@
+function getFileReviewsKey(mrPath) {
+  return `${mrPath}-file-reviews`;
+}
+
+export function getReviewsForMergeRequest(mrPath) {
+  const reviewsForMr = localStorage.getItem(getFileReviewsKey(mrPath));
+  let reviews = {};
+
+  if (reviewsForMr) {
+    try {
+      reviews = JSON.parse(reviewsForMr);
+    } catch (err) {
+      reviews = {};
+    }
+  }
+
+  return reviews;
+}
+
+export function setReviewsForMergeRequest(mrPath, reviews) {
+  localStorage.setItem(getFileReviewsKey(mrPath), JSON.stringify(reviews));
+
+  return reviews;
+}
+
+export function isFileReviewed(reviews, file) {
+  const fileReviews = reviews[file.file_identifier_hash];
+
+  return file?.id && fileReviews?.length ? new Set(fileReviews).has(file.id) : false;
+}
+
+export function reviewable(file) {
+  return Boolean(file.id) && Boolean(file.file_identifier_hash);
+}
+
+export function markFileReview(reviews, file, reviewed = true) {
+  const usableReviews = { ...(reviews || {}) };
+  let updatedReviews = usableReviews;
+  let fileReviews;
+
+  if (reviewable(file)) {
+    fileReviews = new Set([...(usableReviews[file.file_identifier_hash] || [])]);
+
+    if (reviewed) {
+      fileReviews.add(file.id);
+    } else {
+      fileReviews.delete(file.id);
+    }
+
+    updatedReviews = {
+      ...usableReviews,
+      [file.file_identifier_hash]: Array.from(fileReviews),
+    };
+
+    if (updatedReviews[file.file_identifier_hash].length === 0) {
+      delete updatedReviews[file.file_identifier_hash];
+    }
+  }
+
+  return updatedReviews;
+}