Question

How to find a number in an array that appears once in Node.js

Answer 1

// indexOf(searchElement, fromIndex)

function get_single_number(arr) {
    for (let i = 0; i < arr.length; i++) {
        if (arr.indexOf(arr[i], arr.indexOf(arr[i]) + 1) === -1) {
            return arr[i];
        }    
    };
    
    return -1;
};
    
 
const arr = new Array(3, 2, 1, 2, 3, 3, 1, 6, 9, 7, 7, 9, 9); 
       
console.log(get_single_number(arr)); 

   
   
/*
run:
   
6
   
*/

 

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