attr.js

/**
 * attribute accessor utility
 */

var LENGTH_ATTR = 2;

var CSS_PROPERTIES = {
  'alignment-baseline': 1,
  'baseline-shift': 1,
  'clip': 1,
  'clip-path': 1,
  'clip-rule': 1,
  'color': 1,
  'color-interpolation': 1,
  'color-interpolation-filters': 1,
  'color-profile': 1,
  'color-rendering': 1,
  'cursor': 1,
  'direction': 1,
  'display': 1,
  'dominant-baseline': 1,
  'enable-background': 1,
  'fill': 1,
  'fill-opacity': 1,
  'fill-rule': 1,
  'filter': 1,
  'flood-color': 1,
  'flood-opacity': 1,
  'font': 1,
  'font-family': 1,
  'font-size': LENGTH_ATTR,
  'font-size-adjust': 1,
  'font-stretch': 1,
  'font-style': 1,
  'font-variant': 1,
  'font-weight': 1,
  'glyph-orientation-horizontal': 1,
  'glyph-orientation-vertical': 1,
  'image-rendering': 1,
  'kerning': 1,
  'letter-spacing': 1,
  'lighting-color': 1,
  'marker': 1,
  'marker-end': 1,
  'marker-mid': 1,
  'marker-start': 1,
  'mask': 1,
  'opacity': 1,
  'overflow': 1,
  'pointer-events': 1,
  'shape-rendering': 1,
  'stop-color': 1,
  'stop-opacity': 1,
  'stroke': 1,
  'stroke-dasharray': 1,
  'stroke-dashoffset': 1,
  'stroke-linecap': 1,
  'stroke-linejoin': 1,
  'stroke-miterlimit': 1,
  'stroke-opacity': 1,
  'stroke-width': LENGTH_ATTR,
  'text-anchor': 1,
  'text-decoration': 1,
  'text-rendering': 1,
  'unicode-bidi': 1,
  'visibility': 1,
  'word-spacing': 1,
  'writing-mode': 1
};


function getAttribute(node, name) {
  if (CSS_PROPERTIES[name]) {
    return node.style[name];
  } else {
    return node.getAttributeNS(null, name);
  }
}

function setAttribute(node, name, value) {
  var hyphenated = name.replace(/([a-z])([A-Z])/g, '$1-$2').toLowerCase();

  var type = CSS_PROPERTIES[hyphenated];

  if (type) {

    // append pixel unit, unless present
    if (type === LENGTH_ATTR && typeof value === 'number') {
      value = String(value) + 'px';
    }

    node.style[hyphenated] = value;
  } else {
    node.setAttributeNS(null, name, value);
  }
}

function setAttributes(node, attrs) {

  var names = Object.keys(attrs), i, name;

  for (i = 0, name; (name = names[i]); i++) {
    setAttribute(node, name, attrs[name]);
  }
}

/**
 * Gets or sets raw attributes on a node.
 *
 * @param  {SVGElement} node
 * @param  {Object} [attrs]
 * @param  {String} [name]
 * @param  {String} [value]
 *
 * @return {String}
 */
export default function attr(node, name, value) {
  if (typeof name === 'string') {
    if (value !== undefined) {
      setAttribute(node, name, value);
    } else {
      return getAttribute(node, name);
    }
  } else {
    setAttributes(node, name);
  }

  return node;
}