对象数组为id添加金额

Question

我的问题是如何通过id创建其他数组来正确添加对象数组的值，例如，我有：

var array = [{"key":"1","amount":200},{"key":"2","amount":200},{"key":"1","amount":200}];

var resultArray=[{"key":"1","amount":400},{"key":"2","amount":200}]