Convert decimal to binary recursively

Build the binary digits of a non-negative integer as a decimal-looking number.

JavaScript Version 1.0.0 · MIT · .md

function decToBinary(num) { return num === 0 ? 0 : (num % 2) + 10 * decToBinary(Math.floor(num / 2)); }

Input & expected output

10

1010

The edge case

0

0

Know the limits

• The result is a number whose digits are bits, so the lab stops at 65,535 to stay exact. For real work use num.toString(2).
• The original ~~ truncation is replaced with Math.floor.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Clamp a number to a range — Keep a number inside an inclusive minimum and maximum.
• Round to a number of digits — Apply decimal scaling and JavaScript rounding for display-oriented values.
• Add an ordinal suffix to a number — Append st, nd, rd or th to a positive integer.