Push Only Unique Elements In An Array

I have array object(x) that stores json (key,value) objects. I need to make sure that x only takes json object with unique key. Below, example 'id' is the key, so i don't want to s

Solution 1:

would this accomplish what you're looking for? https://jsfiddle.net/gukv9arj/3/

x = [
    {"id":"item1","val":"Items"},
    {"id":"item1","val":"Items"},
    {"id":"item2","val":"Items"}
];    

var clickId = [];
var list = JSON.parse(x);
$.each(list, function(index, value){
    if(clickId.indexOf(value.id) === -1){
        clickId.push(value.id);
    }
});

Solution 2:

You can't use inArray() because you are searching for an object.

I'd recommend rewriting a custom find using Array.some() as follows.

var x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}]    

var clickId = "item1";
var found = x.some(function(value) {
  return value.id === clickId;
});
alert(found);

Solution 3:

Almost 6 years later i ended up in this question, but i needed to fill a bit more complex array, with objects. So i needed to add something like this.

var values = [
  {value: "value1", selected: false},
  {value: "value2", selected: false}
  //there cannot be another object with value = "value1" within the collection.
]

So I was looking for the value data not to be repeated (in an object's array), rather than just the value in a string's array, as required in this question. This is not the first time i think in doing something like this in some JS code.

So i did the following:

let valueIndex = {};
let values = []
//I had the source data in some other and more complex array. 
for (const index in assetsArray) 
{
    const element = assetsArray[index];
    if (!valueIndex[element.value])
    {
        valueIndex[element.value] = true;
        values.push({
            value: element.value,
            selected: false
        });
    }
}

I just use another object as an index, so the properties in an object will never be repated. This code is quite easy to read and surely is compatible with any browser. Maybe someone comes with something better. You are welcome to share! Hopes this helps someone else.

Solution 4:

JS objects are great tools to use for tracking unique items. If you start with an empty object, you can incrementally add keys/values. If the object already has a key for a given item, you can set it to some known value that is use used to indicate a non-unique item.

You could then loop over the object and push the unique items to an array.

var itemsObj = {};
var itemsList = [];
x = [{"id":"item1","val":"foo"},
    {"id":"item2","val":"bar"},
    {"id":"item1","val":"baz"},
    {"id":"item1","val":"bez"}];

for (var i = 0; i < x.length; i++) {
    var item = x[i];
    if (itemsObj[item.id]) {
        itemsObj[item.id] = "dupe";
    }
    else {
        itemsObj[item.id] = item;
    }
}

for (var myKey in itemsObj) {
    if (itemsObj[myKey] !== "dupe") {
        itemsList.push(itemsObj[myKey]);
    }
}

console.log(itemsList);

See a working example here: https://jsbin.com/qucuso

If you want a list of items that contain only the first instance of an id, you can do this:

var itemsObj = {};
var itemsList = [];
x = [{"id":"item1","val":"foo"},
    {"id":"item2","val":"bar"},
    {"id":"item1","val":"baz"},
    {"id":"item1","val":"bez"}];

for (var i = 0; i < x.length; i++) {
    var item = x[i];
    if (!itemsObj[item.id]) {
        itemsObj[item.id] = item;
        itemsList.push(item);
    }
}

console.log(itemsList);

Solution 5:

This is late but I did something like the following:

let MyArray = [];
MyArray._PushAndRejectDuplicate = function(el) {
    if (this.indexOf(el) == -1) this.push(el)
    else return;
} 

MyArray._PushAndRejectDuplicate(1); // [1]
MyArray._PushAndRejectDuplicate(2); // [1,2]
MyArray._PushAndRejectDuplicate(1); // [1,2]