Module `JSX`

JSX module

The JSX module provides functions to render HTML elements in a declarative style.

  let html: string = JSX.render(

    <div>

      <h1> {JSX.string("Hello, World!")} </h1>

    </div>

  );

  let html: string = JSX.render (

    <div>

      <h1>(JSX.string "Hello, World!")</h1>

    </div>

  );

type element

An abstract type that represents a JSX.element

val pp : ?width:int -> element -> string

Pretty-print a JSX.element as a formatted HTML string.

This uses the pretty_expressive optimal printer to produce indented, human-readable HTML. The width parameter (default 80) controls the target page width: elements that fit within the width stay on one line, while longer content is broken across lines with 2-space indentation.

  let html: string = JSX.pp(

    <div>

      <h1> {JSX.string("Hello, World!")} </h1>

    </div>

  );



  Printf.printf("%s", html);

  /* <div>

       <h1>Hello, World!</h1>

     </div> */

  let html: string = JSX.pp (

    <div>

      <h1>(JSX.string "Hello, World!")</h1>

    </div>

  )



  Printf.printf "%s" html

  (* <div>

       <h1>Hello, World!</h1>

     </div> *)

val render : element -> string

Render a JSX.element as a string.

This function takes a JSX.element and converts it into its corresponding HTML string representation.

  let html: string = JSX.render(

    <div>

      <h1> {JSX.string("Hello, World!")} </h1>

    </div>

  );



  Printf.printf("%s", html); /* <div><h1>Hello, World!</h1></div> */

  let html: string = JSX.render (

    <div>

      <h1>(JSX.string "Hello, World!")</h1>

    </div>



  Printf.printf "%s" html (* <div><h1>Hello, World!</h1></div> *)

val render_to_channel : Stdlib.out_channel -> element -> unit

Render a JSX.element directly to an output channel.

This function writes the HTML representation directly to the channel, avoiding the intermediate string allocation that render requires.

  JSX.render_to_channel(stdout,

    <div>

      <h1> {JSX.string("Hello, World!")} </h1>

    </div>

  );

  JSX.render_to_channel stdout (

    <div>

      <h1>(JSX.string "Hello, World!")</h1>

    </div>

  );

val render_streaming : (string -> unit) -> element -> unit

Render a JSX.element using a streaming callback function.

This function renders the element and passes the result to the callback function, useful for frameworks that support streaming responses.

  JSX.render_streaming(html => Dream.write(stream, html),

    <div>

      <h1> {JSX.string("Hello, World!")} </h1>

    </div>

  );

  JSX.render_streaming (fun html -> Dream.write stream html) (<div>

    <h1>(JSX.string "Hello, World!")</h1>

  </div>)

val float : float -> element

Helper to render a float.

This function helps in rendering a float value as a JSX element.

  let element : JSX.element = JSX.float(3.14);

  let element : JSX.element = JSX.float 3.14

val fragment : children:element list -> unit -> element

val int : int -> element

Helper to render an integer.

This function helps in rendering an integer value as a JSX element.

  let element : JSX.element = JSX.int(42);

  let element : JSX.element = JSX.int 42

val list : element list -> element

Helper to render a list of elements.

This function takes a list of JSX elements and returns a single JSX element that contains all of them. This is useful for rendering dynamic lists of elements.

  let element : JSX.element =

    JSX.list([ JSX.string("Item 1"), JSX.string("Item 2"), JSX.string("Item 3") ]);

  let element : JSX.element =

    JSX.list

      [ JSX.string "Item 1"; JSX.string "Item 2"; JSX.string "Item 3" ]

val array : element array -> element

Helper to render an array of elements.

This function takes an array of JSX elements and returns a single JSX element that contains all of them. This is useful for rendering dynamic arrays of elements.

  let element : JSX.element =

    JSX.array

      [| JSX.string("Item 1"), JSX.string("Item 2"), JSX.string("Item 3") |]

  let element : JSX.element =

    JSX.array

      [| JSX.string "Item 1"; JSX.string "Item 2"; JSX.string "Item 3" |]

type attribute =
  string
  * [ `Bool of bool | `Int of int | `Float of float | `String of string ]

Represents an attribute of an HTML element. It consists of a name and a value which can be of several types.

This is used by the ppx to create the attributes of the HTML element, and rarely used directly.

val node : string -> attribute list -> element list -> element

The function to create an HTML DOM Node.

It takes a tag name, a list of attributes, and a list of child elements to create an HTML node.

  let link : JSX.element =

     JSX.node("a",

       [ ("href", `String("https://ocaml.org") ],

       [ JSX.string("OCaml") ]);

  let link : JSX.element =

    JSX.node "a"

      [ ("href", `String "https://ocaml.org") ]

      [ JSX.string "OCaml" ]

val null : element

Helper to represent nullability in JSX.

This is useful to represent and pattern match against null or empty elements.

  let element : JSX.element = JSX.null;

  let element : JSX.element = JSX.null

val string : string -> element

Helper to represent an element as a string.

This function allows you to directly render a string as a JSX element.

  let element : JSX.element = JSX.string("Hello, World!");

  let element : JSX.element = JSX.string "Hello, World!"

val text : string -> element

A deprecated function to render a text string.

This function is deprecated in favor of JSX.string.

  let element : JSX.element = JSX.text("Hello, World!");

  let element : JSX.element = JSX.text "Hello, World!"

deprecated Use JSX.string instead

val format : ('a, unit, string, element) Stdlib.format4 -> 'a

Helper to render formatted text as a JSX element.

This formats a string using Printf-style directives and then renders the result as escaped text, just like JSX.string.

  let element : JSX.element = JSX.format("Hello %s #%i", name, count);

  let element : JSX.element = JSX.format "Hello %s #%i" name count

val unsafe : string -> element

Helper to bypass HTML encoding and treat output as unsafe. This can lead to HTML escaping problems, XSS injections, and other security concerns. Use with caution.

A common use case for bypassing the HTML encoding is to render a script or style tag.

  let content: string = "Raw HTML";

  let script: JSX.element = <script>{content}</script>

  let content: string = "Raw HTML" in

  let script: JSX.element = <script> content </script>

val escape : Stdlib.Buffer.t -> string -> unit

Escape a string and write it directly to a buffer.

This escapes ampersand, less-than, greater-than, apostrophe, and double-quote characters.

This is an advanced function used mostly by the PPX for optimized rendering. Most users should prefer JSX.string.

  let buf = Buffer.create(256);

  JSX.escape(buf, "<script>");

  Buffer.contents(buf); /* "&lt;script&gt;" */

  let buf = Buffer.create 256 in

  JSX.escape buf "<script>";

  Buffer.contents buf (* "&lt;script&gt;" *)

val write : Stdlib.Buffer.t -> element -> unit

Write an element directly to a buffer.

This is an advanced function used mostly by the PPX for optimized rendering when building HTML strings incrementally.

  let buf = Buffer.create(256);

  JSX.write(buf, (JSX.string "Hello"));

  Buffer.contents(buf); /* "Hello" */

  let buf = Buffer.create 256 in

  JSX.write buf (JSX.string "Hello");

  Buffer.contents buf (* "Hello" *)

Module JSX

Module `JSX`