Add snap utils methods

app/util/snaps/index.js

@@ -0,0 +1,35 @@
+import { satisfies as satisfiesSemver } from 'semver';
+import { SNAP_BLOCKLIST } from './snap-blocklist';
+
+/**
+ * Checks if provided snaps are on the block list.
+ *
+ * @param snapsToCheck - An object containing snap ids and other information.
+ * @param blocklist - An object containing snap ids, version or shasum of the blocked snaps.
+ * @returns An object structure containing snaps block information.
+ */
+const checkSnapsBlockList = async (snapsToCheck, blocklist) =>
+  Object.entries(snapsToCheck).reduce((acc, [snapId, snapInfo]) => {
+    const blockInfo = blocklist.find(
+      (blocked) =>
+        (blocked.id === snapId &&
+          satisfiesSemver(snapInfo.version, blocked.versionRange, {
+            includePrerelease: true,
+          })) ||
+        // Check for null/undefined for a case in which SnapController did not return
+        // a valid message. This will avoid blocking all snaps in the given case.
+        // Avoid having (undefined === undefined).
+        (blocked.shasum ? blocked.shasum === snapInfo.shasum : false),
+    );
+
+    acc[snapId] = blockInfo
+      ? {
+          blocked: true,
+          reason: blockInfo.reason,
+          infoUrl: blockInfo.infoUrl,
+        }
+      : { blocked: false };
+    return acc;
+  }, {});
+
+export { checkSnapsBlockList, SNAP_BLOCKLIST };