dom-layer/src/node/patcher/attrs-n-s.js

Virtual DOM implementation.

/**
 * SVG namespaces.
 */
var namespaces = {
  xlink: 'http://www.w3.org/1999/xlink',
  xml: 'http://www.w3.org/XML/1998/namespace',
  xmlns: 'http://www.w3.org/2000/xmlns/'
};

/**
 * Maintains state of element namespaced attributes.
 *
 * @param  Object element   A DOM element.
 * @param  Object previous  The previous state of attributes.
 * @param  Object attrs     The attributes to match on.
 * @return Object attrs     The element attributes state.
 */
function patch(element, previous, attrs) {
  if (!previous && !attrs) {
    return attrs;
  }
  var attrName, ns, name, value, split;
  previous = previous || {};
  attrs = attrs || {};

  for (attrName in previous) {
    if (previous[attrName] && !attrs[attrName]) {
      split = splitAttrName(attrName);
      ns = namespaces[split[0]];
      name = split[1];
      element.removeAttributeNS(ns, name);
    }
  }
  for (attrName in attrs) {
    value = attrs[attrName];
    if (previous[attrName] === value) {
      continue;
    }
    if (value) {
      split = splitAttrName(attrName);
      ns = namespaces[split[0]];
      name = split[1];
      element.setAttributeNS(ns, name, value);
    }
  }
  return attrs;
}

function splitAttrName(attrName) {
  return attrName.split(':');
}

module.exports = {
  patch: patch,
  namespaces: namespaces
};