14-1、includes()

<script>
    // 判断字符串中是否含有某些字符

    // 1.基本用法
    // console.log('abc'.includes('a'))
    // console.log('abc'.includes('ab'))
    // console.log('abc'.includes('bc'))
    // console.log('abc'.includes('ac')) //false

    // 2.第二个参数
    // 表示开始搜索的位置，默认是0
    // console.log('abc'.includes('a', 0))
    // console.log('abc'.includes('a', 1)) // false

    // 3.应用
    // https://www.imooc.com/course/list
    // https://www.imooc.com/course/list?c=fe&sort=pop&name=value

    let url = 'https://www.imooc.com/course/list'
    const addURLParam = (url, name, value) => {
        url += url.includes('?') ? '&' : '?';

        url += `${name}=${value}`
        return url;
    }

    url = addURLParam(url, 'c', 'fe')
    console.log(url);
    url = addURLParam(url, 'sort', 'pop')
    console.log(url)
</script>