fix(firestore): Change asserts to throw argumentError

Author: MichaelVerdon

packages/cloud_firestore/cloud_firestore/lib/src/firestore.dart

@@ -88,18 +88,13 @@ class FirebaseFirestore extends FirebasePluginPlatform {
 
   /// Gets a [CollectionReference] for the specified Firestore path.
   CollectionReference<Map<String, dynamic>> collection(String collectionPath) {
-    assert(
-      collectionPath.isNotEmpty,
-      'a collectionPath path must be a non-empty string',
-    );
-    assert(
-      !collectionPath.contains('//'),
-      'a collection path must not contain "//"',
-    );
-    assert(
-      isValidCollectionPath(collectionPath),
-      'a collection path must point to a valid collection.',
-    );
+    if (collectionPath.isEmpty) {
+      throw ArgumentError('A collection path must be a non-empty string.');
+    } else if (collectionPath.contains('//')) {
+      throw ArgumentError('A collection path must not contain "//".');
+    } else if (!isValidCollectionPath(collectionPath)) {
+      throw ArgumentError('A collection path must point to a valid collection.');
+    }
 
     return _JsonCollectionReference(this, _delegate.collection(collectionPath));
   }
@@ -214,14 +209,13 @@ class FirebaseFirestore extends FirebasePluginPlatform {
 
   /// Gets a [Query] for the specified collection group.
   Query<Map<String, dynamic>> collectionGroup(String collectionPath) {
-    assert(
-      collectionPath.isNotEmpty,
-      'a collection path must be a non-empty string',
-    );
-    assert(
-      !collectionPath.contains('/'),
-      'a collection path passed to collectionGroup() cannot contain "/"',
-    );
+    if (collectionPath.isEmpty) {
+      throw ArgumentError('A collection path must be a non-empty string.');
+    }
+    if (collectionPath.contains('/')) {
+      throw ArgumentError(
+        'A collection path passed to collectionGroup() cannot contain "/".');
+    }
 
     return _JsonQuery(this, _delegate.collectionGroup(collectionPath));
   }
@@ -237,18 +231,13 @@ class FirebaseFirestore extends FirebasePluginPlatform {
 
   /// Gets a [DocumentReference] for the specified Firestore path.
   DocumentReference<Map<String, dynamic>> doc(String documentPath) {
-    assert(
-      documentPath.isNotEmpty,
-      'a document path must be a non-empty string',
-    );
-    assert(
-      !documentPath.contains('//'),
-      'a collection path must not contain "//"',
-    );
-    assert(
-      isValidDocumentPath(documentPath),
-      'a document path must point to a valid document.',
-    );
+    if (documentPath.isEmpty) {
+      throw ArgumentError('A document path must be a non-empty string.');
+    } else if (documentPath.contains('//')) {
+      throw ArgumentError('A document path must not contain "//".');
+    } else if (!isValidDocumentPath(documentPath)) {
+      throw ArgumentError('A document path must point to a valid document.');
+    }
 
     return _JsonDocumentReference(this, _delegate.doc(documentPath));
   }