diff --git a/libraries/overleaf-editor-core/lib/blob.js b/libraries/overleaf-editor-core/lib/blob.js
index 8acd0b6dcd..49e23fb862 100644
--- a/libraries/overleaf-editor-core/lib/blob.js
+++ b/libraries/overleaf-editor-core/lib/blob.js
@@ -40,6 +40,11 @@ class Blob {
 
   static NotFoundError = NotFoundError
 
+  /**
+   * @param {string} hash
+   * @param {number} byteLength
+   * @param {number} [stringLength]
+   */
   constructor(hash, byteLength, stringLength) {
     this.setHash(hash)
     this.setByteLength(byteLength)
@@ -63,14 +68,14 @@ class Blob {
 
   /**
    * Hex hash.
-   * @return {?String}
+   * @return {String}
    */
   getHash() {
     return this.hash
   }
 
   setHash(hash) {
-    assert.maybe.match(hash, Blob.HEX_HASH_RX, 'bad hash')
+    assert.match(hash, Blob.HEX_HASH_RX, 'bad hash')
     this.hash = hash
   }
 
@@ -83,7 +88,7 @@ class Blob {
   }
 
   setByteLength(byteLength) {
-    assert.maybe.integer(byteLength, 'bad byteLength')
+    assert.integer(byteLength, 'bad byteLength')
     this.byteLength = byteLength
   }
 
diff --git a/libraries/overleaf-editor-core/lib/file_data/index.js b/libraries/overleaf-editor-core/lib/file_data/index.js
index 0e6f50325f..e7ab920de9 100644
--- a/libraries/overleaf-editor-core/lib/file_data/index.js
+++ b/libraries/overleaf-editor-core/lib/file_data/index.js
@@ -63,20 +63,14 @@ class FileData {
    */
   static createLazyFromBlobs(blob, rangesBlob) {
     assert.instance(blob, Blob, 'FileData: bad blob')
-    if (blob.getStringLength() == null) {
-      return new BinaryFileData(
-        // TODO(das7pad): see call-sites
-        // @ts-ignore
-        blob.getHash(),
-        blob.getByteLength()
-      )
+    const stringLength = blob.getStringLength()
+    if (stringLength == null) {
+      return new BinaryFileData(blob.getHash(), blob.getByteLength())
     }
     return new LazyStringFileData(
-      // TODO(das7pad): see call-sites
-      // @ts-ignore
       blob.getHash(),
       rangesBlob?.getHash(),
-      blob.getStringLength()
+      stringLength
     )
   }
 
diff --git a/libraries/overleaf-editor-core/lib/file_data/string_file_data.js b/libraries/overleaf-editor-core/lib/file_data/string_file_data.js
index 04d486b6b0..2613c30ebc 100644
--- a/libraries/overleaf-editor-core/lib/file_data/string_file_data.js
+++ b/libraries/overleaf-editor-core/lib/file_data/string_file_data.js
@@ -142,12 +142,8 @@ class StringFileData extends FileData {
         trackedChanges: this.trackedChanges.toRaw(),
       }
       const rangesBlob = await blobStore.putObject(ranges)
-      // TODO(das7pad): Provide interface that guarantees hash exists?
-      // @ts-ignore
       return { hash: blob.getHash(), rangesHash: rangesBlob.getHash() }
     }
-    // TODO(das7pad): Provide interface that guarantees hash exists?
-    // @ts-ignore
     return { hash: blob.getHash() }
   }
 }
diff --git a/services/history-v1/storage/lib/blob_store/index.js b/services/history-v1/storage/lib/blob_store/index.js
index 6f5632a595..1e9c9c6758 100644
--- a/services/history-v1/storage/lib/blob_store/index.js
+++ b/services/history-v1/storage/lib/blob_store/index.js
@@ -79,23 +79,12 @@ function getBackend(projectId) {
 }
 
 async function makeBlobForFile(pathname) {
-  async function getByteLengthOfFile() {
-    const stat = await fs.promises.stat(pathname)
-    return stat.size
-  }
-
-  async function getHashOfFile(blob) {
-    const stream = fs.createReadStream(pathname)
-    const hash = await blobHash.fromStream(blob.getByteLength(), stream)
-    return hash
-  }
-
-  const blob = new Blob()
-  const byteLength = await getByteLengthOfFile()
-  blob.setByteLength(byteLength)
-  const hash = await getHashOfFile(blob)
-  blob.setHash(hash)
-  return blob
+  const { size: byteLength } = await fs.promises.stat(pathname)
+  const hash = await blobHash.fromStream(
+    byteLength,
+    fs.createReadStream(pathname)
+  )
+  return new Blob(hash, byteLength)
 }
 
 async function getStringLengthOfFile(byteLength, pathname) {