retry fetch properly if recieved 401

src/token-pool.js

@@ -215,16 +215,14 @@ class TokenPool {
       pretokens.push({ token, blindFactor });
     }
 
-    const response = await fetch(`${API_BASE_URL}/tokens/new`, {
-      method: 'POST',
-      headers: {
-        'Authorization': `Bearer ${accessToken}`,
-        'Content-Type': 'application/json',
-      },
-      body: JSON.stringify({
-        blindTokens,
-      }),
-    });
+    let response = await this._fetchNewTokens(accessToken, blindTokens);
+    if (response.status === 401) {
+      // try to refresh token and try again if authorization failed
+      // as the token technically could have expired by the time the request
+      // arives
+      const accessToken = await AccessToken.get();
+      response = await this._fetchNewTokens(accessToken, blindTokens);
+    }
     if (response.ok) {
       const { tokens } = await response.json();
       const res = [];
@@ -246,9 +244,19 @@ class TokenPool {
       }));
       console.warn(`Adding ${res.length} tokens to acquired pool`);
       this.tokens.push(...res);
-    } else if (response.status === 401) {
-      // refresh the access token. This will call generateTokens if the refresh is successful
-      AccessToken.refresh();
     }
   }
+
+  async _fetchNewTokens(accessToken, blindTokens) {
+    return fetch(`${API_BASE_URL}/tokens/new`, {
+      method: 'POST',
+      headers: {
+        'Authorization': `Bearer ${accessToken}`,
+        'Content-Type': 'application/json',
+      },
+      body: JSON.stringify({
+        blindTokens,
+      }),
+    });
+  }
 }