How can I check if the array of objects have duplicate property values?

javascript arrays unique
be-codified picture be-codified · Jun 9, 2015 · Viewed 123.4k times · Source

I need some help with iterating through array, I keep getting stuck or reinventing the wheel.

values = [
    { name: 'someName1' },
    { name: 'someName2' },
    { name: 'someName1' },
    { name: 'someName1' }
]

How could I check if there are two (or more) same name value in array? I do not need a counter, just setting some variable if array values are not unique. Have in mind that array length is dynamic, also array values.

Answer

Amir Popovich picture Amir Popovich · Jun 9, 2015

Use array.prototype.map and array.prototype.some:

var values = [
    { name: 'someName1' },
    { name: 'someName2' },
    { name: 'someName4' },
    { name: 'someName2' }
];

var valueArr = values.map(function(item){ return item.name });
var isDuplicate = valueArr.some(function(item, idx){ 
    return valueArr.indexOf(item) != idx 
});
console.log(isDuplicate);

JSFIDDLE.

Related questions

Get all unique values in a JavaScript array (remove duplicates)

I have an array of numbers that I need to make sure are unique. I found the code snippet below on the internet and it works great until the array has a zero in it. I found this other script …

Read More
Remove duplicate values from JS array

I have a very simple JavaScript array that may or may not contain duplicates. var names = ["Mike","Matt","Nancy","Adam","Jenny","Nancy","Carl"]; I need to remove the duplicates and put the unique values in a new array. I could …

Read More
How to get distinct values from an array of objects in JavaScript?

Assuming I have the following: var array = [ {"name":"Joe", "age":17}, {"name":"Bob", "age":17}, {"name":"Carl", "age": 35} ] What is the best way to be able to get an array of all of the distinct ages such that I get an result …

Read More