Question

如果我有一个代表购物车的对象数组（在React中）

[ { id: 1, qty: 1 } ]

将一个项目添加到此state会是一种巧妙的方式吗？

我需要检查数组是否包含具有该id的对象，如果有，则更新它的数量，否则只需创建一个添加此新对象的新数组元素。

我试图用功能风格的新ES6语法编写这个问题......这就是我到目前为止所做的......

let initialState = []

  export default function shoppingCart(state=initialState, action) {
    switch(action.type) {
        case 'ADD_TO_CART':
            // check the array of objects and only act on the one we are interested in 
            let newQty = action.payload.qty
            console.log("state : ", state)
            for(let i = 0; i < state.length; i++) {
               if (state[i].id === action.payload.id) {
                   newQty = state[i].qty + action.payload.qty
                   console.log("QTY : " + newQty)
               }
           }
           //Obviously this will not work if the {id ...} already exists
           return [ ... state, {id:action.payload.id, qty:newQty} ] // todo: update this to contain the payload with qty included

       case 'REMOVE_FROM_CART':
           return state.filter(elem => elem.id !== action.payload.id)
       default:
           return state
   }
}

Answer 1

您可以使用Array.prototype.splice将数组项替换为另一个：

animate

React Reducer函数返回对象数组

1 个答案: