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

Actual answer: https://stackoverflow.com/a/46317662/1549191

Register a math handlebar and perform all mathematical operations.

app.engine('handlebars', exphbs({
  helpers:{
    // Function to do basic mathematical operation in handlebar
    math: function(lvalue, operator, rvalue) {lvalue = parseFloat(lvalue);
        rvalue = parseFloat(rvalue);
        return {
            "+": lvalue + rvalue,
            "-": lvalue - rvalue,
            "*": lvalue * rvalue,
            "/": lvalue / rvalue,
            "%": lvalue % rvalue
        }[operator];
    }
}}));
app.set('view engine', 'handlebars');

Then you can directly perform operation in your view.

    {{#each myArray}}
        <span>{{math @index "+" 1}}</span>
    {{/each}}

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}}

I believe you can use...

{{math @index "+" 1}}