Initial implementation for generating thread JSON files

src/bones/collection/Iterable.ts

@@ -78,8 +78,11 @@ export abstract class Iterable<T> {
             throw new Error('Chunk size must be at least 1')
         }
 
+        const total = await this.count()
         while ( true ) {
-            const items = await this.range(this.index, this.index + size - 1)
+            // Bound the RHS index by the max # of items in case the source
+            // doesn't gracefully handle out-of-bounds access
+            const items = await this.range(this.index, Math.min(this.index + size - 1, total - 1))
             this.index += items.count()
 
             try {