var list = [1, 2, 3, 4, 5, 6, 7, 8]
var index = list.map(item => item).indexOf(8)
console.log(index) //7
var array = [{
name: "aa"
}, {
name: "bb"
}, {
name: "cc"
}, {
name: "dd"
}, {
name: "ee"
}]
var line= array.map(item => item.name).indexOf('dd')
console.log(line) //3