context is not defined JavaScript

问题

So referring to the original problem I have here Google Maps Javascript V3 Uncaught TypeError: Cannot read property 'offsetWidth' of null and after doing a lot of googling, I have found a solution which I thought would be workable which is this How to append multiple Google Maps areas to divs using Handlebars.

However, I have implemented mine in the following way

var EmployeeView = function(employee){
  this.render = function(){
    $('body').append(this.el);
      // inside the new div, put the Handlebars template, with the data from the employee
      this.el.html(EmployeeView.template(employee)).ready( function() {
        var mapOptions = {
          center: new google.maps.LatLng(-34.397, 150.644),
          zoom: 8
        };
        var map = new google.maps.Map(document.getElementById("map-canvas"), mapOptions);
      });
      return this;
    };

    this.initialize = function(){
      this.el=$("</div>");
      window.localStorage.removeItem('paramId');
      console.log('removed');
      window.localStorage.setItem('paramId',employee);
      console.log('added ' + employee.id);    
    };
    this.initialize();
  }

EmployeeView.template = Handlebars.compile($("#employee-tpl").html());

Not sure if thats the right way of 'referring' to that solution but now, whenever I run the page, the following error is thrown Uncaught ReferenceError: context is not defined

Anyone got any ideas? and to add, my html is as follows

<body>
<script id="employee-tpl" type="text/x-handlebars-template">
  <div class='details'>
    <img class='employee-image' src='img/{{firstName}}_{{lastName}}.jpg' />
    <ul>
      <li><a href="#map/{{this.id}}">See on map</a></li>         
      <li>Share with friends</li>
      <li><div id="map-canvas"/></li>
    </ul>
  <script src="lib/iscroll.js"></script>
  <script src="lib/handlebars.js"></script>
  <script src="lib/jquery-1.8.2.min.js"></script>
  <script src="js/storage/cafe-memory-store.js"></script>
  <script type="text/javascript" src="http://maps.google.com/maps/api/js?APIKEY&sensor=true"></script> 
  <script src="js/MapView.js"></script>
  <script src="js/EmployeeView.js"></script>
  <script src="js/HomeView.js"></script>
  <script src="js/main.js"></script>
</body>

回答1:

In this line:

$("employee-tpl").append(HTMLtemplate(context))

You are passing an undefined function and one undefined variable (context). context should contain he id parameter you defined in your HandlebarJS template to be replaced

<a href="#map/{{this.id}}">See on map</a>

HTMLTemplate in your case is EmployeeView.template which holds the HandlebarJS compiled template: it is a function that receives as arguments the context variable ( or maybe the employee variable?)

If I got it right your code should be:

var EmployeeView = function(employee){

  this.render = function(){
    $('body').append(this.el);
    // inside the new div, put the Handlebars template, with the data from the employee
    this.el.html(EmployeeView.template(employee))).ready( function() {
        var mapOptions = {
        center: new google.maps.LatLng(-34.397, 150.644),
        zoom: 8

        };
        var map = new google.maps.Map(document.getElementById("map-canvas"), mapOptions);
    });


    return this;
  };



  this.initialize = function(){
    this.el=.$("</div>");
    window.localStorage.removeItem('paramId');
    console.log('removed');
    window.localStorage.setItem('paramId',employee);
    console.log('added ' + employee.id);    
  };
  this.initialize();


}

EmployeeView.template = Handlebars.compile($("#employee-tpl").html());

I think you have to pass employee to the template because I saw first_name and last_name in the template.

来源：https://stackoverflow.com/questions/20373278/context-is-not-defined-javascript

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javascript

jquery

html

templates

handlebars.js