What is sort ..?

The sort() method sorts the elements of an array in place and returns the array. This is what we get in MDN docs.

const months = ['March', 'Jan', 'Feb', 'Dec'];
months.sort();
console.log(months);
//  output:   ["Dec", "Feb", "Jan", "March

The above code really worked as what we expected. But, when it comes to Numbers the situation is Unexpected..!

const array1 = [1, 30, 4, 21, 100000];
array1.sort();
console.log(array1);
//  output:  [1, 100000, 21, 30, 4]

meme sort.jpg Credit: Reddit

Why ..?

By default Array. sort() method will work for alphabets without a problem. but, when it comes to numbers it causes problems.

let us resolve what is going on

Without argument

const array1 = [1, 30, 4, 21, 100000];
array1.sort();
console.log(array1);
//  output: Array [1, 100000, 21, 30, 4]

With comparator

const array1 = [1, 30, 4, 21, 100000];
array1.sort((a,b) => a-b) ;
console.log(array1);
//Output: [1, 4, 21, 30, 100000]

const numbers= [1,30,4,21,100000];
numbers.sort(  (a,b) => {

  if (a < b) {
    return -1;
  }
  if (a > b) {
    return 1;
  }
  return 0;
});


//Output: [1, 4, 21, 30, 100000]

If (a < b) function returns -1, a will go before b (1 < 30) so, Number 1 is first then 30 is second and it continues the operation until the condition is okay
If (a > b) function returns 1, b will go before a (30 > 4) so, Number 4 will go first number 30 will place after a

If(a=b) then Nothing will change in order

What if you want descending order ..?

No Problem

const numbers = [1, 30, 4, 21, 100000];

numbers.sort((a,b) => b-a);

console.log(numbers);

// output:  [100000, 30, 21, 4, 1]

Conclusion

Array. sort() method invoked without arguments sorts the elements alphabetically. That’s why using an array. sort() to sort numbers in ascending order doesn’t work.

This is what I understood about Array. sort() method in javascript