Giraffe.Htmx/src/ViewEngine.Htmx

Giraffe.ViewEngine.Htmx

This package enables htmx support within the Giraffe view engine.

htmx version: 4.0.0-alpha6

Upgrading from v2.x: see the migration guide for changes, which are plentiful. htmx switches from XMLHTTPRequest to fetch, and many changes are related to the new event cycle.

Inheritance is now explicit; to have an attribute's value inherited to its children, wrap the attribute in hxInherited (ex. hxInherited (_hxTarget "#main")). Values can be appended to inherited values as well using the hxAppend modifier.

Several constructs have been marked obsolete in this release, and will be removed from the first production release of v4. With the exception of _hxDisable, though (which now functions as the deprecated _hxDisabledElt did), this should not introduce compile errors. Rather, this package will raise warnings for deprecated constructs, along with suggestions of what to use instead.

Setup

1. Install the package.
2. Prior to using the attribute or support modules, open Giraffe.ViewEngine.Htmx.

Use

Following Giraffe View Engine's lead, there are a set of attribute functions for htmx; for many of the attributes, there are also helper modules to assist with typing the values. The example below utilizes both:

let autoload =
    div [ _hxGet "/this/data"; _hxTrigger HxTrigger.Load ] [ str "Loading..." ]

Support modules include:

• HxConfig (new in v4)
• HxEncoding
• HxHeaders
• HxParams (removed in v4)
• HxRequest (renamed to HxConfig)
• HxSwap (requires open Giraffe.Htmx)
• HxTrigger
• HxVals

Htmx.Script.local creates an XmlNode to load the package-provided htmx library. There are also two XmlNodes that will load the htmx script from jsdelivr; Htmx.Script.cdnMinified loads the minified version, and Htmx.Script.cdnUnminified loads the unminified version (useful for debugging). When using the CDN nodes and a Content Security Policy (CSP) header, cdn.jsdelivr.net needs to be listed as an allowable script-src.

This also supports fragment rendering, providing the flexibility to render an entire template, or only a portion of it (based on the element's id attribute).

Learn

htmx's attributes and these attribute functions map one-to-one. There are two exceptions:

• _hxBoost implies true; use _hxNoBoost to set it to false.
• _hxSwapWithTransition renders the standard hx-swap attribute and appends transition:true to the specified swap value.

The htmx hx-on attribute supports multiple events if they are separated with a newline (\n) character. The value provided to this attribute will be attribute-escaped, but in testing, it was interpreted correctly.

The support modules contain named properties for known values (as illustrated with HxTrigger.Load above). A few of the modules are more than collections of names, though:

• HxRequest has a Configure function, which takes a list of strings; the other functions in the module allow for configuring the request.

HxRequest.Configure [ HxRequest.Timeout 500 ] |> _hxRequest 

• HxTrigger is (by far) the most complex of these modules. Most uses won't need that complexity; however, complex triggers can be defined by piping into or composing with other functions. For example, to define an event that responds to a shift-click anywhere on the document, with a delay of 3 seconds before firing:

HxTrigger.Click
|> HxTrigger.Filter.Shift
|> HxTrigger.FromDocument
|> HxTrigger.Delay "3s"
|> _hxTrigger

// or

(HxTrigger.Filter.Shift >> HxTrigger.FromDocument >> HxTrigger.Delay "3s") HxTrigger.Click
|> _hxTrigger