Update stringifyFilter to support CompositeFilters

Author: MarkDuckworth

packages/firestore/src/core/target.ts

@@ -891,9 +891,25 @@ export function compositeFilterEquals(
 /** Returns a debug description for `filter`. */
 export function stringifyFilter(filter: Filter): string {
   debugAssert(
-    filter instanceof FieldFilter,
-    'stringifyFilter() only supports FieldFilters'
+    (filter instanceof FieldFilter) || (filter instanceof CompositeFilter),
+    'stringifyFilter() only supports FieldFilters and CompositeFilters'
   );
+  if (filter instanceof FieldFilter) {
+    return stringifyFieldFilter(filter);
+  }
+  else if (filter instanceof CompositeFilter) {
+    return stringifyCompositeFilter(filter);
+  }
+  else {
+    return 'Filter';
+  }
+}
+
+export function stringifyCompositeFilter(filter: CompositeFilter): string {
+  return filter.op.toString() + ` {` + filter.getFilters().map(stringifyFilter).join(' ,') + '}';
+}
+
+export function stringifyFieldFilter(filter: FieldFilter): string {
   return `${filter.field.canonicalString()} ${filter.op} ${canonicalId(
     filter.value
   )}`;