一、常用方法
数组:let numbers = [1, 2, 3, 4, 5, 6, 7];
1、filter——返回该函数会返回true的项组成的数组
// filter
let filterResult = numbers.filter(function (item, index, array) {
return item > 2;
});
console.log(filterResult); // [3, 4, 5, 6, 7]
2、map——返回每次函数调用的结果组成的数组
// 当数组为dom集合时,numbers.map(function (index, item, array)
let mapResult = numbers.map(function (item, index, array) {
return item * 2;
});
console.log(mapResult); // [2, 4, 6, 8, 10, 12, 14]
3、some——如果该函数任意一项返回true,则返回true;
let someResult = numbers.some(function (item, index, array) {
return item > 2;
});
console.log(someResult); // true
4、every——如果该函数每一项都返回true,则返回true;
let everyResult = numbers.every((item, index, array)=> {
return item > 2;
});
console.log(everyResult); // false
5、find—返回第一个符合条件的项
let everyResult = numbers.find((item, index, array)=> {
return item > 2;
});
console.log(everyResult); // 3
6、findIndex—返回第一个符合条件的位置,如果所有成员都不符合条件,则返回-1
let everyResult = numbers.findIndex((item, index, array)=> {
return item > 2;
});
console.log(everyResult); // 2
7、includes—判断数组是否包含指定元素,如果是返回 true,否则false
numbers.includes(2); //true
numbers.includes(10); //false
二、计算场景
1、arr1是原数组,arr2是操作后数组,求目标数组(保留删除项disabled=0)
var arr1 = [{
"disabled": 1,
"id": 159,
"dictKey": "warehouse_dept_1",
"dictValue": "仓储一部"
},{
"disabled": 1,
"id": 160,
"dictKey": "warehouse_dept_2",
"dictValue": "仓储二部"
},{
"disabled": 1,
"id": 161,
"dictKey": "warehouse_dept_3",
"dictValue": "仓储三部"
}
]
var arr2 = [{
"disabled": 1,
"id": 159,
"dictKey": "warehouse_dept_1",
"dictValue": "仓储一部11"
},
{
"disabled": 1,
"id": 160,
"dictKey": "warehouse_dept_2",
"dictValue": "仓储二部"
},
{
"disabled": 1,
"dictValue": "ceshi"
},
]
let commonIds = arr2.filter((x) => arr1.find((y) => y.id === x.id));
let deleteIds = arr1.filter((x) => !arr2.find((y) => y.id === x.id));
let adds = arr2.filter((x) => !x.id);
deleteIds = deleteIds.map((item) => {
item.disabled = 0;
return item;
});
let result = [...commonIds, ...adds, ...deleteIds];