a more sophisticated clamp

clamp.js

/**
 * Restrict a value to within specified boundaries.
 *  - If only the `value` is specified, the boundaries are 0 and 1.
 *  - If only the `value` and boundary `a` are specified, the boundaries
 *    are 0 and `a`.
 *  - If the value and both boundaries `a` and `b` are specified, the
 *    boundaries are `a` and `b`.
 *  Clamp does not enforce the proper ordering of the boundaries. 
 *  Therefore, clamp(2, 1, 3) and clamp(2, 3, 1) will return the same
 *  result.
 * 
 * @param {Number} value Numeric value to clamp between boundaries
 * @param {Number} (optional) a "Lower" boundary or 1 in undefined
 * @param {Number} (optional) b "Upper" boundary or 0 if undefined
 * @returns {Number} value between boundaries `a` and `b` inclusive
 */
function clamp(value, a, b) {
  var max, min;
  if (arguments.length < 3) {
    b = 0;
    if (arguments.length < 2) {
      a = 1;
    }
  }
  max = Math.max(a, b);
  min = Math.min(a, b);
  return (value < min) ? min : (value > max) ? max : value;
}