Looking at previous item in handlebars loop MeteorJS

Question

I have a template in which I want to generate some HTML only if the current item has some different fields from the previous item.

{{#each item}}
  // if previous item.ar == current item.var, do X
  // else, do Y
{{/each}

How can I access the previous item?

Answer 1

You can transform your data via your helper. Here's an example using kittens... because everyone loves kittens right?

Template.feline.helpers({
  kittens: function() {
    // fetch some kittens
    var kittens = Cats.find({_id: {$in: this.kittens}}).fetch();

    // keep track of the last kitten
    previousKitten = {};

    return _.map(kittens, function(kitten) {
      // add an isAwesome property based on the previous kitten
      if (previousKitten.eyeColor === kitten.eyeColor)
        kitten.isAwesome = true;

      previousKitten = kitten
      return kitten;
    });
  }
});

Now inside of the {{#each kittens}} iterator, you can test for the existence of isAwesome.