Function styleString

d3-3.2.8/d3.js:7606–7613

(b)

      this.style.removeProperty(name);
    }
    function styleString(b) {
      return b == null ? styleNull : (b += "", function() {
        var a = d3_window.getComputedStyle(this, null).getPropertyValue(name), i;
        return a !== b && (i = d3_interpolate(a, b), function(t) {
          this.style.setProperty(name, i(t), priority);
        });
      });
    }
    return d3_transition_tween(this, "style." + name, value, styleString);
  };
  d3_transitionPrototype.styleTween = function(name, tween, priority) {