ESlint提示Unnecessary use of boolean literals in conditional expression

使用三元运算符时，判断返回的是true或者false，ESlint提示Unnecessary use of boolean literals in conditional expression

var txt = '22   '
var sms = txt.trim()?true:false

解决方法：使用双重否定，迫使结果变成一个布尔类型

var txt = '22   '
var sms = !!txt.trim()