conveyal/modeify

/**
 * Module dependencies.
 */

var debug = require('debug')('reactive:attr-binding');
var utils = require('./utils');

/**
 * Expose `AttrBinding`.
 */

module.exports = AttrBinding;

/**
 * Initialize a new attribute binding.
 *
 * @param {Reactive} view
 * @param {Element} node
 * @param {Attribute} attr
 * @api private
 */

function AttrBinding(reactive, node, attr) {
  var self = this;
  this.reactive = reactive;
  this.node = node;
  this.attr = attr;
  this.text = attr.value;
  this.props = utils.interpolationProps(this.text);
  this.subscribe();
  this.render();
}

/**
 * Subscribe to changes.
 */

AttrBinding.prototype.subscribe = function(){
  var self = this;
  var reactive = this.reactive;
  this.props.forEach(function(prop){
    reactive.sub(prop, function(){
      self.render();
    });
  });
};

/**
 * Render the value.
 */

AttrBinding.prototype.render = function(){
  var attr = this.attr;
  var text = this.text;
  var reactive = this.reactive;
  var model = reactive.model;

  // TODO: delegate most of this to `Reactive`
  debug('render %s "%s"', attr.name, text);
  attr.value = utils.interpolate(text, function(prop, fn){
    if (fn) {
      return fn(model, reactive.view, utils.call);
    } else {
      return reactive.get(model, prop);
    }
  });
};