一、数组
- array.indexOf
let arr = ['1', '2', '3', '4'];
let index = arr.indexOf('3');
console.log(index);// 2
2.array.includes(searchElement,[fromIndex])
fromIndex:从该索引处开始查找 searchElement。(非必填)
如果为负值,则按升序从 array.length + fromIndex 的索引开始搜索。默认为 0。
let numbers = [12, 5, 8, 130, 44];
let result = numbers.includes(8);//true
result = numbers.includes(118);// false
let numbers = [12, 5, 8, 130, 44];
let result = numbers.includes(8,[1]);console.log(result);//true
let result = numbers.includes(8,[3]);console.log(result);//false
3.array.find
// ---------- 元素是普通字面值 ----------
let numbers = [12, 5, 8, 130, 44];
let result = numbers.find(item => {
return item > 8;
});// 12
// ---------- 元素是对象 ----------
let items = [
{id: 1, name: 'something'},
{id: 2, name: 'anything'},
{id: 3, name: 'nothing'},
{id: 4, name: 'anything'}
];
let item = items.find(item => {
return item.id == 3;
});//{id: 3, name: "nothing"}
4.array.findIndex
返回数组中满足条件的第一个元素的索引(下标), 如果没有找到,返回-1
// ---------- 元素是普通字面值 ----------
let numbers = [12, 5, 8, 130, 44];
let result = numbers.findIndex(item => {
return item > 8;
});// 0
// ---------- 元素是对象 ----------
let items = [
{id: 1, name: 'something'},
{id: 2, name: 'anything'},
{id: 3, name: 'nothing'},
{id: 4, name: 'anything'}
];
let index = items.findIndex(item => {
return item.id == 3;
});// 2
5.some
find返回满足条件的第一项;some找到符合条件的项后返回布尔值
var arr = [{
name: "小提莫",
value: "0"
}, {
name: "小鲁班",
value: "1"
}]
var result_one = arr.some(function(item) {
if (item.name == "小提莫") {
return true;
}
})
console.log(result_one );//true
6.$.inArray(searchElement, arr)
使用jquery的inArray方法,该方法返回元素在数组中的下标,如果不存在与数组中,那么返回-1
var arr=['aaa','bbb','ccc','ddd','eee'];
var a= $.inArray('bbb',arr);
console.log(a);//1
二、对象
1.Obj.hasOwnProperty('name') 是都包含name属性
let obj={name:"Lily",sex:"女"};
let isHas=obj.hasOwnProperty("name");
console.log(isHas);//true
2.in关键字 是否有某个属性
var obj={name:"Lily",sex:"女"};
const hasName="name" in obj;
console.log(hasName);//true
三、字符串
1.indexOf
var str ="123";
console.log(str.indexOf("12")!=-1);//true
2.search()
var str="123";
console.log(str.search("23")!=-1);//true
3.match()
var str="123";
var reg=RegExp(/23/);
if(str.match(reg)){
console.log("包含");
}
4.test()
var str="123,345,567";
var reg=RegExp(/345/);
console.log(reg.test(str));//true
5.exec()
var str="123,345,678,99";
reg=RegExp(/345/)
if(reg.exec(str)){
console.log("包含");
}