Meteor + Blaze - If else statement

Question

Looking at this Using Blaze guide, it seems Blaze supports {{#if}} and {{else}} statements, but I have't seen examples of an if-else statement. Is this supported in Blaze? Or do I have to do an additional if block inside the else block, which can get ugly.

I tried {{else if}}, but that gave an error.

{{#if en}}{{text.en}}{{else if tc}}{{text.tc}}{{/if}} 

Answer 1

Spacebars uses the same control flow structure as handlebars so the answer is the same as this one. In your case:

{{#if en}}   {{text.en}} {{else}}   {{#if tc}}     {{text.tc}}   {{/if}} {{/if}} 

Side note - one of the nice things about jade is that it supports else if.

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Sometimes a better alternative is to move the logic into a helper like this:

Template.myTemplate.helpers({   textValue: function() {     if (this.en) {       return this.text.tc;     } else if (this.tc) {       return this.text.tc;     }   } }); 

<template name="myTemplate">   <p>{{textValue}}</p> </template> 

Answer 2

Following on from @David Wheldon's excellent answer, it's also worth noting that you can pass parameters to your JavaScript helper functions from your Blaze template.

So, for example the code below selectively renders the options for a select list by calling the helper method with the line isSelected region customerCompany:

    {{#if isSelected region customerCompany}}         <option value={{region._id}} selected>{{region.name}}</option>     {{else}}         <option value={{region._id}}>{{region.name}}</option>     {{/if}} 

and then in the js file:

isSelected: function (region, customer) {      return customer.salesRegionId === region._id; }, 

This approach of passing in your variables to your helpers is generally recommended to avoid the confusion that can the arise with the changing meaning of the this keyword when using templates.