Question

How to sort an array so that null values always come last in JavaScript

Answer 1

function nullLast(ascending) {
  return function (a, b) {
    if (a === b) {
        return 0;
    }
    else if (a === null) {
        return 1;
    }
    else if (b === null) {
        return -1;
    }
    else if (ascending) {
        return a < b ? -1 : 1;
    }
    else { 
        return a < b ? 1 : -1;
    }
  };
}


const arr = ["php", "c++", null, "typescript", "c", null, "nodejs", null, "javascript"]; 
 
arr.sort(nullLast(true));
console.log(arr);

arr.sort(nullLast(false));  
console.log(arr);

   
    
    
    
/*
run:
    
["c", "c++", "javascript", "nodejs", "php", "typescript", null, null, null]
["typescript", "php", "nodejs", "javascript", "c++", "c", null, null, null]
    
*/

 

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