Modify forEachEnvelopeItem so it can be exited early

Author: timfish

packages/utils/src/envelope.ts

@@ -41,31 +41,32 @@ export function addItemToEnvelope<E extends Envelope>(envelope: E, newItem: E[1]
 /**
  * Convenience function to loop through the items and item types of an envelope.
  * (This function was mostly created because working with envelope types is painful at the moment)
+ *
+ * If the callback returns true, the rest of the items will be skipped.
  */
 export function forEachEnvelopeItem<E extends Envelope>(
   envelope: Envelope,
-  callback: (envelopeItem: E[1][number], envelopeItemType: E[1][number][0]['type']) => void,
-): void {
+  callback: (envelopeItem: E[1][number], envelopeItemType: E[1][number][0]['type']) => boolean | void,
+): boolean {
   const envelopeItems = envelope[1];
-  envelopeItems.forEach((envelopeItem: EnvelopeItem) => {
+
+  for (const envelopeItem of envelopeItems) {
     const envelopeItemType = envelopeItem[0].type;
-    callback(envelopeItem, envelopeItemType);
-  });
+    const result = callback(envelopeItem, envelopeItemType);
+
+    if (result) {
+      return true;
+    }
+  }
+
+  return false;
 }
 
 /**
  * Returns true if the envelope contains any of the given envelope item types
  */
 export function envelopeContainsItemType(envelope: Envelope, ...types: EnvelopeItemType[]): boolean {
-  let isType = false;
-
-  forEachEnvelopeItem(envelope, (_, type) => {
-    if (types.includes(type)) {
-      isType = true;
-    }
-  });
-
-  return isType;
+  return forEachEnvelopeItem(envelope, (_, type) => types.includes(type));
 }
 
 /**