Helpers

Handlebars helpers are plain JavaScript functions you can invoke from your stack group and stack configuration, and template files.

note

Helpers are supported only when using Handlebars templating engine.

You register your own custom Handlebars helpers by adding .js files to helpers dir.

Each file must export an object with the following properties:

• name = Helper name you use in configuration.
• fn = Function to invoked when the helpers is invoked. Must not be asynchronous function.

Examples

Here are some examples of different helpers.

Helper with no arguments

This helper returns the current date and takes no arguments.

helpers/timestamp.js

module.exports = {
  name: 'timestamp',
  fn: () => Date.now().getTime(),
}

This is how you'd use it in your files:

Description: Current timestamp is {{timestamp}}

And this is what the final rendered file looks like:

Description: Current timestamp is 1647678689175

Helper with single argument

This helper accepts a single string argument and returns it converted in upper case.

helpers/upper-case.js

module.exports = {
  name: 'upper-case',
  fn: (str) => str.toUpperCase(),
}

This is how you'd use it in your files:

Description: Hello {{upper-case 'world'}}

And this is what the final rendered file looks like:

Description: Hello WORLD

Helper with two arguments

This helper accepts two arguments and returns a boolean value indicating if the two arguments are equal.

helpers/eq.js

module.exports = {
  name: 'eq',
  fn: (a, b) => a === b,
}

This is how you'd use it in your files:

Parameters: 
  EnableFeature: {{eq var.environment 'prod'}}

And this is what the final rendered file looks like assuming var.environment is "prod":

Parameters:
  EnableFeature: true