Adding offset to {{@index}} when looping through items in Handlebars

Question

I\'m iterating over a list in Handlebars using the built-in each helper. Within the each block, I\'m referencing the current loop index

Answer 1

The handlebars-helpers library has a fairly thorough mathematics library in lib/math.js, including a general purpose {{add a b}} helper defined as follows:

/**
 * Return the product of a plus b.
 *
 * @param {Number} a
 * @param {Number} b
 * @api public
 */
helpers.add = function(a, b) {
  return a + b;
};

If you don't want to copy and paste this into your project and you have the possibility to use npm, you can get this dependency as follows:

npm install handlebars-helpers --save

Then, you can register the math helpers as follows:

const handlebars = require('handlebars'),
  handlebarsHelpers = require('handlebars-helpers');

handlebarsHelpers.math({
  handlebars: handlebars
});

Answer 2

I believe you can use...

{{math @index "+" 1}}

Answer 3

Throwing my solution in here. CSS counters.

body {
  counter-reset: section;                     /* Set a counter named 'section', and its initial value is 0. */
}

h3::before {
  counter-increment: section;                 /* Increment the value of section counter by 1 */
  content: counter(section);                  /* Display the value of section counter */
}

I was stuck on this and it was a nicer solution compared to adding a new helper.

Answer 4

there is an easy way to incitement with the {{@index}} value.

solution is to call the funtion and pass the @index value o it and than on JS, use helper to return @index + 1

here is go

{{incitement @index}}

and here is code for the js

Handlebars.registerHelper("incitement", function (inindex) {
  return inindex + 1
});

Answer 5

I was using nodejs and express-handlebars as template engine and facing same problem. And this is how I managed to solve.

You can create a folder and a js file inside it where you can create your own custom helpers that takes index and returns incrementing it by 1.

module.exports = {
    formatIndex: function(index)  {
        return index+1;
    }
}

Remember to register helper in your application(in my case app.js). I have used express-handlebars so I have reistered helper in this way:

app.engine('handlebars', exphbs({defaultLayout: 'home', helpers: { formatIndex }}));

Note: You have to import formatIndex before registering.

Then you can use it in your view as:

{{#each assignments}}
     <div>{{formatIndex @index }}</div>
{{/if}}

Answer 6

Handlebars gives you the possibility to write a custom helper that handles this situation, e.g. a helper function that lets you perform calculations on expressions like addition and subtraction etc.

Below function registers a new helper, which simply increments a value by 1:

var Handlebars = require('handlebars');

Handlebars.registerHelper("inc", function(value, options)
{
    return parseInt(value) + 1;
});

You can then use it within the handlebar expression using the inc keyword, like:

{{inc @index}}