1 files changed, 65 insertions, 0 deletions
diff --git a/app/assets/javascripts/repository/commits_service.js b/app/assets/javascripts/repository/commits_service.js
new file mode 100644
index 00000000000..504efaea8cc
--- /dev/null
+++ b/app/assets/javascripts/repository/commits_service.js
@@ -0,0 +1,65 @@
+import axios from '~/lib/utils/axios_utils';
+import { joinPaths } from '~/lib/utils/url_utility';
+import { normalizeData } from 'ee_else_ce/repository/utils/commit';
+import createFlash from '~/flash';
+import { COMMIT_BATCH_SIZE, I18N_COMMIT_DATA_FETCH_ERROR } from './constants';
+
+let requestedOffsets = [];
+let fetchedBatches = [];
+
+export const isRequested = (offset) => requestedOffsets.includes(offset);
+
+export const resetRequestedCommits = () => {
+  requestedOffsets = [];
+  fetchedBatches = [];
+};
+
+const addRequestedOffset = (offset) => {
+  if (isRequested(offset) || offset < 0) {
+    return;
+  }
+
+  requestedOffsets.push(offset);
+};
+
+const removeLeadingSlash = (path) => path.replace(/^\//, '');
+
+const fetchData = (projectPath, path, ref, offset) => {
+  if (fetchedBatches.includes(offset) || offset < 0) {
+    return [];
+  }
+
+  fetchedBatches.push(offset);
+
+  const url = joinPaths(
+    gon.relative_url_root || '/',
+    projectPath,
+    '/-/refs/',
+    ref,
+    '/logs_tree/',
+    encodeURIComponent(removeLeadingSlash(path)),
+  );
+
+  return axios
+    .get(url, { params: { format: 'json', offset } })
+    .then(({ data }) => normalizeData(data, path))
+    .catch(() => createFlash({ message: I18N_COMMIT_DATA_FETCH_ERROR }));
+};
+
+export const loadCommits = async (projectPath, path, ref, offset) => {
+  if (isRequested(offset)) {
+    return [];
+  }
+
+  // We fetch in batches of 25, so this ensures we don't refetch
+  Array.from(Array(COMMIT_BATCH_SIZE)).forEach((_, i) => {
+    addRequestedOffset(offset - i);
+    addRequestedOffset(offset + i);
+  });
+
+  // Since a user could scroll either up or down, we want to support lazy loading in both directions
+  const commitsBatchUp = await fetchData(projectPath, path, ref, offset - COMMIT_BATCH_SIZE);
+  const commitsBatchDown = await fetchData(projectPath, path, ref, offset);
+
+  return commitsBatchUp.concat(commitsBatchDown);
+};