liang14658fox

Appearance

判断变量是数组还是对象 ​

  1. 使用Object.prototype.toString.call() 利用 Object.prototype.toString.call()方法将该变量转化为代表其类型的string
js
Object.prototype.toString.call(arr) // [object Array]

Object.prototype.toString.call(obj) // [object Object]
Object.prototype.toString.call(arr) // [object Array]

Object.prototype.toString.call(obj) // [object Object]
  1. 使用Array.isArray()
js
Array.isArray(arr) // true

Array.isArray(obj) // false
Array.isArray(arr) // true

Array.isArray(obj) // false

封装数组对象排序方法 ​

js
compare(prop) {
    return function(a, b) {
        return b[prop] - a[prop]  // 降序
        // return a[prop] - b[prop]  // 升序
    }
},
// 比如arrList对象中根据score属性进行从大到小的排序
this.arrList = this.arrList.sort(this.compare('score'))
compare(prop) {
    return function(a, b) {
        return b[prop] - a[prop]  // 降序
        // return a[prop] - b[prop]  // 升序
    }
},
// 比如arrList对象中根据score属性进行从大到小的排序
this.arrList = this.arrList.sort(this.compare('score'))

按照数组中的日期对象进行排序 ​

js
// 如何对数组进行排序，从最早到最新，反之亦然？
const arr = [
  {id: 1, value : "value1", date: "2018-08-08", time: "15:27:17"},
  {id: 2, value : "value2", date: "2018-08-09", time: "12:27:17"},
  {id: 3, value : "value3", date: "2018-08-10", time: "17:27:17"},
  {id: 4, value : "value4", date: "2018-08-10", time: "01:27:17"},
  {id: 5, value : "value5", date: "2018-08-10", time: "09:27:17"},
  {id: 6, value : "value6", date: "2018-08-10", time: "23:27:17"},
  {id: 7, value : "value7", date: "2018-08-10", time: "16:27:17"},
  {id: 8, value : "value8", date: "2018-08-11", time: "10:27:17"}
];

arr.sort((a, b) => a.date.localeCompare(b.date) || a.time.localeCompare(b.time));  // 
console.log(arr);
// 如何对数组进行排序，从最早到最新，反之亦然？
const arr = [
  {id: 1, value : "value1", date: "2018-08-08", time: "15:27:17"},
  {id: 2, value : "value2", date: "2018-08-09", time: "12:27:17"},
  {id: 3, value : "value3", date: "2018-08-10", time: "17:27:17"},
  {id: 4, value : "value4", date: "2018-08-10", time: "01:27:17"},
  {id: 5, value : "value5", date: "2018-08-10", time: "09:27:17"},
  {id: 6, value : "value6", date: "2018-08-10", time: "23:27:17"},
  {id: 7, value : "value7", date: "2018-08-10", time: "16:27:17"},
  {id: 8, value : "value8", date: "2018-08-11", time: "10:27:17"}
];

arr.sort((a, b) => a.date.localeCompare(b.date) || a.time.localeCompare(b.time));  // 
console.log(arr);
js
const arr = [
  {id: 1, value : "value1", date: "2018-08-08", time: "15:27:17"},
  {id: 2, value : "value2", date: "2018-08-09", time: "12:27:17"},
  {id: 3, value : "value3", date: "2018-08-10", time: "17:27:17"},
  {id: 4, value : "value4", date: "2018-08-10", time: "01:27:17"},
  {id: 5, value : "value5", date: "2018-08-10", time: "09:27:17"},
  {id: 6, value : "value6", date: "2018-08-10", time: "23:27:17"},
  {id: 7, value : "value7", date: "2018-08-10", time: "16:27:17"},
  {id: 8, value : "value8", date: "2018-08-11", time: "10:27:17"}
];

arr.sort((a, b) => b.date.localeCompare(a.date) || b.time.localeCompare(a.time));
console.log(arr);
const arr = [
  {id: 1, value : "value1", date: "2018-08-08", time: "15:27:17"},
  {id: 2, value : "value2", date: "2018-08-09", time: "12:27:17"},
  {id: 3, value : "value3", date: "2018-08-10", time: "17:27:17"},
  {id: 4, value : "value4", date: "2018-08-10", time: "01:27:17"},
  {id: 5, value : "value5", date: "2018-08-10", time: "09:27:17"},
  {id: 6, value : "value6", date: "2018-08-10", time: "23:27:17"},
  {id: 7, value : "value7", date: "2018-08-10", time: "16:27:17"},
  {id: 8, value : "value8", date: "2018-08-11", time: "10:27:17"}
];

arr.sort((a, b) => b.date.localeCompare(a.date) || b.time.localeCompare(a.time));
console.log(arr);