# Check if an array have duplicated elements Js

Hi, here some code solutions that will help us to check if an array have duplicated elements or not.

### First Solution

``````function checkForDuplicates(array) {
// To save all the values that are not repited
let helperArray = [];

for (let i = 0; i < array.length; i++) { // To go through every elemebt of the array [1, 3, 5, 4, 5]

// If the helperArray DOES NOT have that "value"
if (helperArray.indexOf(array[i]) !== -1) { // .indexOf("theVALUE") -> will return the position of this value if is in the array
// -1 means that the element is not in te array
// and because we are denying then means that "if that element it is in the array" then return 'Yes values repited!'
return `Yes Values repited, and the value repited is: \${array[i]}` // or return true
}

// The helperArray is saving every element that is not repited
helperArray.push(array[i])
}

return false
}

checkForDuplicates([1, 3, 5, 4, 5]);``````

Result:

### Second Solution

``````function checkForDuplicates(array) {
// To save all the values that are not repited
let helperArray = [];

for (let i = 0; i < array.length; i++) { // To go through every elemebt of the array [1, 3, 5, 4, 5]

// If the helperArray Yes includes this value
if (helperArray.includes(array[i])) {
return `Yes Values repited, and the value repited is: \${array[i]}` // or return true
}

// If helperArray does not include that value then save the value into helperArray
helperArray.push(array[i])
}

return false
}

checkForDuplicates([1, 3, 5, 4, 3]);``````

Result:

### Third solution:

``````let myArray = [1, 3, 5, 4];

let hasDuplicate = myArray.some((val, i) => myArray.indexOf(val) !== i);
console.log('hasDuplicate---->', hasDuplicate)``````

Result:

### Four Solution:

``````function checkForDuplicates(array) {
return new Set(array).size !== array.length
}

checkForDuplicates([1, 3, 5, 4, 1]);``````

Result:

By Cristina Rojas.