Handlebars Helpers

ADL templates are written in Handlebars. On top of the standard Handlebars syntax, ADL registers a set of helper functions that make working with metadata easier — comparing strings, looking up extension properties, generating predictable test data, and so on.

These helpers can be used inside any template. For the concepts, see Templates & Code Generation.

Available helpers

Lookups

• extension_exists — check whether a named extension property exists on a Data Object.
• extension_lookupextension — read the value of an extension property.
• extension_targetdataitemexists — check whether a Data Item exists on the target Data Object.

Strings

• extension_stringcompare — compare two strings.
• extension_stringdiff — diff two strings.
• extension_stringreplace — replace substrings.
• extension_stringwrap — wrap a string with given prefix and suffix.
• extension_replicate — repeat a string N times.
• extension_space — emit N spaces (useful for indentation).

Dates & test data

• extension_now — current timestamp.
• extension_randomdate — random date within a range.
• extension_randomnumber — random number within a range.
• extension_randomstring — random string.

Where these come from

The helpers are registered by ADL’s generation engine. The full implementation lives in the HandlebarsHelpers class in the open-source generation library.