js取值排除undefined、““、null

直接双叹号即可 !!值

当有值时：非空字符串，空数组、空对象；输出为 true；
当没值时：""、null、undefined；输出为false

示例js代码

	let obj1 = ''
    console.log('"":',!!obj1)

    let obj2 = null
    console.log('null:',!!obj2)

    let obj3 = undefined
    console.log('undefined:',!!obj3)

    let obj4 = []
    console.log('有值[]:',!!obj4)

    let obj5 = {
    
    }
    console.log('有值{}:',!!obj5)

    let obj6 = '哈哈'
    console.log('有值"哈哈"：',!!obj6)

控制台结果