javascript check if array contains duplicates code example

Example 1: check if array has same values javascript

const allEqual = arr => arr.every(v => v === arr[0]);
allEqual([1,1,1,1]);  // true

Example 2: javascript check if array has duplicates

function hasDuplicates(array) {
    return (new Set(array)).size !== array.length;
}

Example 3: js check if array of objects contains duplicates

const arrayOfObjCopy = [...arrayOfObj];

Object.keys(arrayOfObjCopy).forEach((key) => {
  arrayOfObjCopy[key] = JSON.stringify(arrayOfObjCopy[key]);
 });

const arrayOfObjhasDuplicates = uniq(arrayOfObjCopy).length != arrayOfObjCopy.length;