Function tween

external/.d3.js:4524–4528

()

function attrTweenNS(fullname, value) {
  var t0, i0;
  function tween() {
    var i = value.apply(this, arguments);
    if (i !== i0) t0 = (i0 = i) && attrInterpolateNS(fullname, i);
    return t0;
  }
  tween._value = value;
  return tween;
}