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Sort

Sorts elements of an array​

  • sort is a mutable function
  • It also returns the same altered array
// Default sorts as strings
let fruits = ["orange", "apple", "banana"];
fruits.sort();
console.log(fruits); // ["apple", "banana", "orange"]

// For numbers, provide a compare function
let numbers = [40, 1, 5, 200];
numbers.sort();
console.log(numbers); // [1, 200, 40, 5] (string order!)

// Correct numeric sort
numbers.sort((a, b) => a - b);
console.log(numbers); // [1, 5, 40, 200]

How works​

  • takes first and second value
  • pass that to function
  • wait for return value
  • based on the return value, it will change position of the first and 2nd element
  • again, takes second and third value then pass to function
  • and so on...

compare​

compareFn(a, b) return valuesort order
> 0sort a after b, e.g., [b, a]
< 0sort a before b, e.g., [a, b]
=== 0keep original order of a and b

Sort - array of Objects​

const students = [
  { name: "Alex", grade: 15 },
  { name: "Devlin", grade: 15 },
  { name: "Eagle", grade: 13 },
  { name: "Sam", grade: 14 },
];
students.sort((firstItem, secondItem) => firstItem.grade - secondItem.grade);