Function normalize

external/.d3.js:14957–14961

(a, b)

}

function normalize(a, b) {
  return (b -= (a = +a))
      ? function(x) { return (x - a) / b; }
      : constants(isNaN(b) ? NaN : 0.5);
}

function clamper(a, b) {
  var t;