Contents
When to use a block helper in HTML?
Control structures typically do not change the current context, instead they decide whether or not to invoke the block based upon some variable. When writing a conditional, you will often want to make it possible for templates to provide a block of HTML that your helper should insert if the conditional evaluates to false.
Can a block helper accept an optional hash?
When the helper values are different, the closing mustache should match the opening helper name. Like regular helpers, block helpers can accept an optional Hash as its final argument. Let’s revisit the list helper and make it possible for us to add any number of optional attributes to the element we will create.
How are Parameters evaluated in a block helper?
Helpers can take parameters, and parameters are evaluated just like expressions used directly inside { {mustache}} blocks. Parameters are passed to helpers in the order that they are passed, followed by the options hash. A common use-case for block helpers is using them to define custom iterators.
Are there any helper functions for m extensions?
This topic contains a number of helper functions commonly used in M extensions. These functions may eventually be moved to the official M library, but for now can be copied into your extension file code. You shouldn’t mark any of these functions as shared within your extension code.
How to find the number of block parameters in a template?
Helpers can determine the number of block parameters referenced by the template via the options.fn.blockParams field, which is an integer count. This value represents the number of block parameters that could be referenced by the child template.
How does the custom block Helper Work in handlebars?
When we register a custom block helper, Handlebars automatically adds an options object as the last parameter to the callback function. This options object has a fn() method that allows us to change the context of the object temporarily to access a certain property.