JavaScript: Reverse the order of the bits in a given integer

Last update on June 08 2022 11:08:46 (UTC/GMT +8 hours)

JavaScript Basic: Exercise-127 with Solution

Write a JavaScript program to reverse the order of the bits in a given integer.

14 -> 00001110 -> 01110000 -> 112
56 -> 00111000 -> 00011100 -> 28
234 -> 11101010 -> 01010111 -> 87

Pictorial Presentation:

JavaScript: Reverse the order of the bits in a given integer.

Sample Solution:

JavaScript Code:

function mirror_bits(n) {
    let t = n.toString(2).split("");
    let str_len = t.length;
    for (let i = 0; i < 8 - str_len; i++) {
        t.unshift("0");
    }
    return parseInt(t.reverse().join(""), 2);
}
// 14 -> 00001110 -> 01110000 -> 112
console.log(mirror_bits(14));
// 56 -> 00111000 -> 00011100 -> 28
console.log(mirror_bits(56));
// 234 -> 11101010 -> 01010111 -> 87
console.log(mirror_bits(234));

Sample Output:

112
28
87

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-127 by w3resource (@w3resource) on CodePen.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join());
arr.splice(2, 0, "Lene");
console.log(arr.join());

Ref: https://bit.ly/2BXbp04