Array gets the specified element, object element property value Index

For an array of primitive type elements , you can use the indexof () artifact directly, return the subscript of the element in the array, and return 1 if not found:

var arr = [1,2,3,4,5];
var index = Arr.indexof (3);  2

For arrays with objects as elements , there is no direct function to use, but there is a filter () method that creates a new array in which the elements in the new array are checked for all elements that match the criteria in the specified array, so that at least you can filter the array elements that match the criteria:

var arr = [
    {name: ' Ming ', age:16},
    {name: ' Dan ', age:18},
{name: ' Yue ', age:22}
]
var Filterarr = Arr.filter (function (Elem, Index,arr) {return
    elem.age>=18
})  //[{name: "Dan", Age:18},{name: "Yue" , age:22}]