Javascript Array mySort(key)

Array.prototype.mySort = function (key) {

 function compare(first, second) {
  
  if (first[key] < second[key]) {
      return -1;//from  w w w .j a  v a2  s  . co m
  }
  
    if (first[key] > second[key]) {
      return 1;
  }
  
    return 0;
 } 
 
 return this.sort(compare);
}


// test array 
var testArray = [
 
 { a: 'a', b: 17 }, 
 { a: 'b', b: 1 }, 
 { name: 'John', b: 10 },
 { age: 20, b: '9' },
 { age: 20, b: -Infinity },
 { a: 'c', b: false },
 { box: 10, b: true },
 { box: 10, b: 'hello' },
 { box: 10, b: { name: 'Kiti' } },
 { age: 20, b: undefined }

];


console.table(testArray.mySort('b')); // -Infinity false 1 true '9' 10 17 Object 'hello' undefined

console.log(testArray.mySort('b') === testArray); // true