我正在尝试从集合任务“step”中添加数组中的对象,而不删除数组中已经存在的对象 queryDocumentSnapshot.ref.set({steps:[{title:newStep,completed:false}]});
alert('This task has been updated'); 但是当我使用set时,它删除了所有旧的字段。如何在不删除的情
*** Terminating app due to uncaught exception 'NSGenericException', reason: '*** Collection <__NSArrayM: 0x17204b070> was mutated while being enumerated.'0 CoreFoundation 0x0000000186acefe0 __