regexper-static/src/js/regexper.js

import parser from './parser/javascript.js';
import Snap from 'snapsvg';
import Q from 'q';

export default class Regexper {
  constructor(root) {
    this.root = root;
    this.form = root.querySelector('#regexp-form');
    this.field = root.querySelector('#regexp-input');
    this.error = root.querySelector('#error');
    this.permalink = root.querySelector('a[data-glyph="link-intact"]');
    this.download = root.querySelector('a[data-glyph="data-transfer-download"]');
    this.percentage = root.querySelector('#progress div');
    this.svg = root.querySelector('#regexp-render svg');

    this.padding = 10;
    this.snap = Snap(this.svg);
  }

  keypressListener(event) {
    var evt;

    if (event.shiftKey && event.keyCode === 13) {
      event.returnValue = false;
      if (event.preventDefault) {
        event.preventDefault();
      }

      evt = document.createEvent('Event');
      evt.initEvent('submit', true, true);
      this.form.dispatchEvent(evt);
    }
  }

  documentKeypressListener(event) {
    if (event.keyCode === 27) {
      parser.cancel();
    }
  }

  submitListener(event) {
    event.returnValue = false;
    if (event.preventDefault) {
      event.preventDefault();
    }

    try {
      this._setHash(this.field.value);
    }
    catch(e) {
      // Most likely failed to set the URL has (probably because the expression
      // is too long). Turn off the permalink and just show the expression
      this.permalinkEnabled = false;
      this.showExpression(this.field.value);
    }
  }

  hashchangeListener() {
    this.permalinkEnabled = true;
    this.showExpression(this._getHash());
  }

  updatePercentage(event) {
    this.percentage.style.width = event.detail.percentage * 100 + '%';
  }

  bindListeners() {
    this.field.addEventListener('keypress', this.keypressListener.bind(this));
    this.form.addEventListener('submit', this.submitListener.bind(this));
    this.root.addEventListener('updateStatus', this.updatePercentage.bind(this));
    this.root.addEventListener('keyup', this.documentKeypressListener.bind(this));
    window.addEventListener('hashchange', this.hashchangeListener.bind(this));
  }

  _setHash(hash) {
    location.hash = encodeURIComponent(hash);
  }

  _getHash() {
    return decodeURIComponent(location.hash.slice(1));
  }

  set state(state) {
    this.root.className = state;
  }

  get state() {
    return this.root.className;
  }

  showExpression(expression) {
    this.field.value = expression;
    this.state = '';

    if (expression !== '') {
      this.state = 'is-loading';

      this.renderRegexp(expression)
        .then(() => {
          this.state = 'has-results';
          this.updateLinks();
        }, (message) => {
          if (message === 'Render cancelled') {
            this.state = '';
          } else {
            throw message;
          }
        })
        .done();
    }
  }

  buildBlobURL(content) {
    var blob = new Blob([content], { type: 'image/svg+xml' });
    window.blob = blob; // Blob object has to stick around for IE
    return URL.createObjectURL(blob);
  }

  updateLinks() {
    try {
      this.download.parentNode.style.display = null;
      this.download.href = this.buildBlobURL(this.svg.parentNode.innerHTML);
    }
    catch(e) {
      // Blobs or URLs created from them don't work here.
      // Giving up on the download link
      this.download.parentNode.style.display = 'none';
    }

    if (this.permalinkEnabled) {
      this.permalink.parentNode.style.display = null;
      this.permalink.href = location.toString();
    } else {
      this.permalink.parentNode.style.display = 'none';
    }
  }

  renderRegexp(expression) {
    this.snap.selectAll('g').remove();

    return Q.fcall(parser.parse.bind(parser), expression.replace(/\n/g, '\\n'))
      .then(null, message => {
        this.state = 'has-error';
        this.error.innerHTML = '';
        this.error.appendChild(document.createTextNode(message));

        throw message;
      })
      .invoke('render', this.snap.group())
      .then(result => {
        var box = result.getBBox();

        result.transform(Snap.matrix()
          .translate(this.padding - box.x, this.padding - box.y));
        this.snap.attr({
          width: box.width + this.padding * 2,
          height: box.height + this.padding * 2
        });
      });
  }
}