regexper-static/src/js/parser/javascript/regexp.js

import _ from 'lodash';
import Q from 'q';
import Base from './base.js';

export default _.extend({}, Base, {
  type: 'regexp',

  _render() {
    var matches = this.matches(),
        matchContainer;

    if (matches.length === 1) {
      return this.proxy(matches[0]);
    } else {
      matchContainer = this.container.group()
        .addClass('regexp-matches')
        .transform(Snap.matrix()
          .translate(20, 0));

      return Q.all(_.map(matches, match => {
        return match.render(matchContainer.group());
      }))
        .then((() => {
          var containerBox,
              paths;

          this.spaceVertically(matches, {
            padding: 5
          });

          containerBox = this.getBBox();
          paths = _.map(matches, match => {
            var box = match.getBBox(),
                direction = box.cy > containerBox.cy ? 1 : -1,
                distance = Math.abs(box.cy - containerBox.cy),
                pathStr;

            if (distance >= 15) {
              pathStr = [
                'M10,{box.cy}m0,{shift}q0,{curve} 10,{curve}',
                'M{containerBox.width},{box.cy}m30,{shift}q0,{curve} -10,{curve}'
              ].join('');
            } else {
              pathStr = [
                'M0,{containerBox.cy}c10,0 10,{anchor.y} 20,{anchor.y}',
                'M{containerBox.width},{containerBox.cy}m40,0c-10,0 -10,{anchor.y} -20,{anchor.y}'
              ].join('');
            }

            return Snap.format(pathStr, {
              containerBox,
              box,
              shift: -10 * direction,
              curve: 10 * direction,
              anchor: {
                x: box.x + 20,
                y: box.cy - containerBox.cy
              }
            });
          });

          paths.push(Snap.format([
            'M0,{box.cy}q10,0 10,-10V{top}',
            'M0,{box.cy}q10,0 10,10V{bottom}',
            'M{box.width},{box.cy}m40,0q-10,0 -10,-10V{top}',
            'M{box.width},{box.cy}m40,0q-10,0 -10,10V{bottom}'
          ].join(''), {
            box: containerBox,
            top: _.first(matches).getBBox().cy + 10,
            bottom: _.last(matches).getBBox().cy - 10
          }));

          this.container.prepend(
            this.container.path(paths.join('')));
        }).bind(this));
    }
  },

  matches() {
    return [this._match].concat(_.map(this._alternates.elements, _.property('match')));
  }
});