6 kyu: Angle Between Clock Hands — Codewars JS

Given a Date (in JS and Ruby) or hours and minutes (in C and Python), return the angle between the two hands of a 12-hour analog clock in radians.

Notes:

• The minute hand always points to the exact minute (there is no seconds hand).
• The hour hand does not «snap» to the tick marks: e.g. at 6:30 the angle is not 0 because the hour hand is already half way between 6 and 7.
• Return the smaller of the angles ( <= π ).
• Return π if the hands are opposite.

Examples

• at noon the angle is: 0
• at 3:00 the angle is: π/2 (90 degrees)
• at 6:00 the angle is: π (180 degrees)
• at 9:00 the angle is: π/2 (90 degrees)

Solution

function handAngle (date) {
  const PI = 3.141592653589793;
  const hour = date.getHours();
  const min = date.getMinutes();
  
  let angle = Math.abs((hour * 30 + min * 0.5) - (min * 6));
  angle = angle < 180 ? angle : 360 - angle;

  return PI * angle / 180;
}