First Reoccurring character

//time complexity 0(n^2)
function FirstReoccuringChar(arr){
    
    for (let i=0;i<arr.length;i++){
        for(let j=i+1;j<arr.length;j++){
            if(arr[i]===arr[j]){
                return arr[i];
            }
        }
    }
    return undefined;
}


// time complexity 0(n)
function FirstReoccuringChar1(arr){
    
    const table={};
    
    for (let ar of arr){
        
        if(!table[arr]){
            table[arr]=1;
        }
        else{
            return ar;
        }
    }
    return 'There is no occuring element in the given array'
}

const result= FirstReoccuringChar1([1,2,2,1,0,5,0]);
console.log('The first reoccuring character is--',result);