JS 判斷數組裏的 數據 | 內容 是否相同 相等

 1. 遍歷 方法

let arr = ['success', 'success', 'success', 'error', 'success' ]

function isEqual (arr = []) {
  let flag = true
  arr.forEach((element, index) => {
     let nextIndex = index + 1
     let nextEle = arr[nextIndex]
     if (nextIndex < arr.length) {
        if (element !== nextEle) flag = false
     }
  })
  return flag
}

// false

 2. every()方法

let arr = ['success', 'success', 'success', 'error', 'success' ]

let flag = 'success'

let result = arr.every(item => item === flag)

result // false