With the sort method built into the JavaScript array objects, we can use it easily to sort arrays. The sort method takes a function that lets us compare 2 entries in the array to let us set the sort order between 2 elements based on the conditions that we specify.
The function that we pass into the sort method takes 2 parameters, the first is an element which we call a, and the second is an element which we call b, and we compare a and b to determine which should be sorted above the other in the array. The sort function expects a number to be returned by the callback.
If the value that’s returned by our function is negative, then a will be in an array index that’s lower than b. That is, a comes before b. If the number is positive, then b will come before a. If the function returns 0, then a and b will stay in their original position.
If we want to shuffle the array, we can just return a random number from it — the value of a or b will not have an impact on the sort. We can once again use the Math.random() method to help us generate a random return value for the function we pass into the sort method. We can write the following code to sort each entry in random order (shuffle the array):
let nums = [49, -151, 88, -133, -164, 78, 117, -25, 76, -40];
nums = nums.sort(() => {
return Math.random() - 0.5
});
console.log(nums);
In the code above, our sort method has a function which generates a random number between -0.5 and 0.5, which means there’s a chance that each element either stays in place or gets shuffled, according to what the sort method will do depending on the return value.
The Math.random() only returns numbers between 0 and 1. However, we can easily make it more useful by extending it in the ways that we did above. We can specify a range between a minimum and a maximum number and Math.random() * (max — min) + min to generate a number between a range. Also, we can pass it into the callback function of the sort method by returning Math.random() — 0.5 to generate a number between -0.5 and 0.5, which means that it can be shuffled (or not) depending on the sign of the generated number and whether it’s 0 or not.
