[javascript] How to get index in Handlebars each helper?

Arrays:

{{#each array}}
    {{@index}}: {{this}}
{{/each}}

If you have arrays of objects... you can iterate through the children:

{{#each array}}
    //each this = { key: value, key: value, ...}
    {{#each this}}
        //each key=@key and value=this of child object 
        {{@key}}: {{this}}
        //Or get index number of parent array looping
        {{@../index}}
    {{/each}}
{{/each}}

Objects:

{{#each object}}
    {{@key}}: {{this}}
{{/each}} 

If you have nested objects you can access the key of parent object with {{@../key}}