✨ Add release path module

src/ssn/releasePaths.ts

@@ -40,13 +40,35 @@ function getFroms({ product, to: releaseTo}: {product: string, to: number}) {
   }
 }
 
-/** Checks whether there is a valid path between our current release and the release we want to update to, and returns true or false.
+/**
+ * Checks whether there is a valid path between our current release and the release we want to update to, and returns an array with
+ * the release path, or an empty array if no path exists.
+ * E.g. for `{ from: 21, to: 24 }`, it returns [[21, 22], [22, 23], [23, 24]].
  * Does not actually look at the manifest.xml file but theorizes on possible patches based on the usually created patches, allowing
  * us to find release pathes for products that have not been released yet.
  */
-export default function findReleasePath({ product, from, to}: {product: string, from: number, to: number}) {
+export default function findReleasePath({ product, from, to}: {product: string, from: number, to: number}): Array<[number, number]> {
-    //TODO: need to recursively get froms until path is found
+  //We assume that "from < to" is true for all patches
-    //TODO: need to ignore patches that we know are bugged (i.e. missing from CDN)
+
-    return getFroms({ product, to }).includes(from);
+  const froms = getFroms({ product, to });
-    //TODO: we also need to return the release path, e.g. [[3, 4], [4, 5], [5, 6]]
+
+  //If we can patch, return immediately
+  if (froms.includes(from)) {
+    return [[from, to]];
+  }
+
+  //Otherwise, check all froms recursively, by checking interim releases
+  const smallerFroms = froms.filter((num) => num > from);
+  //Always prefer shortest release paths (e.g. 1->3 vs. 1->2->3) by ensuring we check smallest froms first
+  smallerFroms.sort();
+
+  for (let i = 0, il = smallerFroms.length; i < il; i += 1) {
+    const interim = smallerFroms[i];
+    const releasePath = findReleasePath({ product, from, to: interim} );
+    if (releasePath.length > 0) {
+      return [...releasePath, [interim, to]];
+    }
+  }
+
+  return [];
 }