style.js

import defaultView from "../window.js";

function styleRemove(name) {
  return function() {
    this.style.removeProperty(name);
  };
}

function styleConstant(name, value, priority) {
  return function() {
    this.style.setProperty(name, value, priority);
  };
}

function styleFunction(name, value, priority) {
  return function() {
    var v = value.apply(this, arguments);
    if (v == null) this.style.removeProperty(name);
    else this.style.setProperty(name, v, priority);
  };
}

export default function(name, value, priority) {
  return arguments.length > 1
      ? this.each((value == null
            ? styleRemove : typeof value === "function"
            ? styleFunction
            : styleConstant)(name, value, priority == null ? "" : priority))
      : styleValue(this.node(), name);
}

export function styleValue(node, name) {
  return node.style.getPropertyValue(name)
      || defaultView(node).getComputedStyle(node, null).getPropertyValue(name);
}