Another Twig Ternary Example


Introduction

Previously in my Simplified Web Development with JSON and the Twig Ternary Operator, I had used JSON that had boolean values. Recently I’ve created another form that has a survey with checkboxes and I stored the JSON with string values instead. This article gives an alternate example of using the Twig ternary operator to handle strings.

The JSON Code

My survey JSON sample looks like the following example:

JSOM_Sample

In the above JSON, the keys represent the survey questions, and the string values represent the checkbox that was chosen. In the above case “strong_A” means “Strong Agree”, and “some_D” means “Somewhat Disagree”. It’s just a simpler way to write/code the JSON and still keep it understandable.

I struggled for a long time on how to handle processing of the JSON data in my Twig template when presenting a view of the form that was submitted. I show the results of the submitted for in a html table with a table row for each question and the selected checkboxes. So one row consists of the question + checkbox1 + checkbox2 + checkbox3 + checkbox4, and a total of 4 questions. So to do this in Twig, I struggle with how to create the for loop.

I thought maybe I could do a Twig for loop using {% for i in 0..3 %} to process each of the 4 checkboxes, and thus I was thinking of using the following JSON code:

JSOM_Sample_Alt

So in the above I would store each checkbox as a boolean in the JSON array, however, this would actually require a lot more Twig code, and a lot of if/else statements. I wanted to simplify my code and reduce the number of lines required.

Problems with Twig If Statements

One way of processing whether any of the checkboxes is selected is by using if/else statements, however, the code gets messy and looks something like the following code sample:

Twig_If_Probs

Notice each html td element has an if/else statement, and a total of 32 lines are used for one table row. This is a lot of code.

Simplifying the Code with the Twig Ternary Operator

I simplified the code by using the Twig ternary operator (as described in the documentation) to replace all the if/else statements. For example, to check my JSON in Twig to see if the “Strongly Agree” checkbox is selected, I use the following code in my html td element:

code

Where in the above “(survey[‘Recommend’] == ‘strong_A’)” does a comparison to see if it matches the string, and if so then show a checked checkbox. The code CheckCode is an html escape code to render a checked checkbox. The code UncheckCode is an empty checkbox.

Example in Twigfiddle

I created a Twigfiddle here to show you the twig working in case you need to see it in action. Also, you will need to see the result in html, so there’s a twig fiddle showing the resultant rendered html in this SyncFiddle.

Enjoy!

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About Alvin Bunk
Hi, I'm a software developer at Taft College.

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