MeteorJS在单击事件中获取MongoDB ID

Question

I have the following mongo collection in my MeteorJS app:

//Server side, load all the images
Images = new Mongo.Collection('images');
Meteor.startup(() => {
  if(Images.find().count() == 0){
    for(var i = 1; i < 23; i++){
      Images.insert({
        src:"img_"+i+".jpg",
        alt:"image "+i
      });
    }
  }
});

I pass that to a template and that works. However, I then want to retrieve the MongoDB id of an image (id that is the primary key/unique ID in MongoDB). I do it with the following code:

//Client side, get the collection and load it to the template
Images =  new Mongo.Collection('images');

Template.images.helpers({images:Images.find()});

Template.images.events({
  'click .js-del-image': (event) => {
    var imageId = event._id;
    console.log(imageId);
  }
});

This gives me undefined . What am I doing wrong? I thought this._id should give me the MongoDB ID.

For the record, This is my template, the _id attribute gets filled out:

<template name="images">
        <div class="row">
      {{#each images}}
      <div class="col-xs-12 col-md-3" id="{{_id}}">
        <div class="thumbnail">
            <img class="js-image img-responsive thumbnail-img" src="{{src}}"
            alt="{{alt}}" />

            <div class="caption">
                <p>{{alt}}</p>
               <button class="js-del-image btn btn-warning">delete</button>
            </div>
         </div>
        </div> <!-- / col -->
      {{/each}}
    </div> <!-- / row -->
</template>

Answer 1

The problem was in the declaration of a function:

• (event) => { ... } seems to have _id of undefined .
• function(event) {...} seems to have the correct context.

See this answer for further information about (event) => {...} vs function(){...} declarations.