为数组所有对象添加一个新属性

1. 为数组所有对象添加一个新属性

     let addKey = copyList.map(item => {
       let obj = {}
       obj['key'] = item.id
       return { ...item, ...obj }
     })

2. 合并两个数组索引所对应的对象

     let arr = [
       { youSay: '你说', 'doGO': 'go' },
       { youSay: '你说', 'doGO': 'go' },
       { youSay: '你说', 'doGO': 'go' },
     ]
   
     let str = [
       { what: '是的呀' },
       { how: '什么呢' },
       { why: '好的呀' },
     ]
     
     
     let letMerge = arr.map((item, index) => {
       return { ...item, ...str[index] }
     })
     console.log('letMerge', letMerge);
   // log value
   0: {youSay: '你说', doGO: 'go', what: '是的呀'}
   1: {youSay: '你说', doGO: 'go', how: '什么呢'}
   2: {youSay: '你说', doGO: 'go', why: '好的呀'}