如何检查文字对象是否在 Javascript 数组中

Question

I have an array & a literal object like this

var arr = [{a: 1}, {a: 2}, {a: 3}];
var e1 = {a: 1};

I want to implement a function (ex: containsObject(e1, arr) ) what should return true in this case.

Please teach me the way without overriding base classes like Array.prototype.indexof

Answer 1

Try this:

 var arr = [{a: 1}, {a: 2}, {a: 3}]; var e1 = {a: 1}; for (var i=0; i<arr.length; i++) { var found = true; for (var key in e1) { if (e1[key] != arr[i][key]) { found = false; break; } } if (found) { alert('found at index ' + i); break; } }

Answer 2

        var arr = [{a: 1}, {a: 2}, {a: 3}];
var e1 = {a: 1};
function containsObject(e1, arr) {
    var i;
    for (i = 0; i < arr.length; i++) {
        if (JSON.stringify(arr[i]) === JSON.stringify(e1)) {
            alert("we found it")
        }else{
            alert(JSON.stringify(e1)+"not equal to"+JSON.stringify(arr[i]))
        }
    }
}
containsObject(e1, arr)

if you don't mind compare them in string, use this way. JSON.stringify() convert object to json string, I think you expect compare them in human vision, then that is it.

I don't think the 2 different object can be compared.they are 2 instance from Object,

Answer 3

This may Help you

function containsObject(e1, arr)
    {
      var k=false;
      ap=arr.filter(function(a){
      if(JSON.stringify(a) === JSON.stringify(e1))
      {k=true; 
       return(true);}
     });
    (k===true)?console.log("in array"):console.log("not in array");
    }
var arr = [{a: 1}, {a: 2}, {a: 3}];
var e1 = {a: 1};
containsObject(e1,arr);

Since array is not containing any method so we can use stringify to compare objects.

Answer 4

This may help you.

function containsObject(e1, arr) {
    var i;
    for (i = 0; i < arr.length; i++) {
        if (arr[i] === e1) {
            return true;
        }
    }

    return false;
}