Snippet of viewPanel.js

viewPanel.js

// ViewPanel class
function ViewPanel(content, script) {
  this.panel = Panel({
    width: sp.prefs['width'],
    height: sp.prefs['height'],
    contentURL: data.url(content),
    contentScriptFile: data.url(script)
  });

  // Using arrow functions to resolve scope issues
  let onWidthChange = () => {
    this.panel.width = sp.prefs['width'];
  }

  let onHeightChange = () => {
    this.panel.height = sp.prefs['height'];
  }

  // listeners on the prefs change
  sp.on('width', onWidthChange);
  sp.on('height', onHeightChange);
}

ViewPanel.prototype.getWidth = function getWidth() {
  return this.panel.width;
};

ViewPanel.prototype.getHeight = function getHeight() {
  return this.panel.height;
};

ViewPanel.prototype.setWidth = function setWidth(width) {
  this.panel.width = width;
};

ViewPanel.prototype.setHeight = function setHeight(height) {
  this.panel.height = height;
};

ViewPanel.prototype.getPanel = function getPanel() {
  return this.panel;
};

exports.ViewPanel = ViewPanel;