fetch

 This article describes a feature or macro function that is experimental and may be subject to change.

fetch() Function

• Introduced in version 1.11.4

Fetches a URI via javascript. Wrapper around XMLHttpRequest().

Usage

let x = fetch(target, [options]);
x.then((response) => {
  }, (failure) => {
  });

Parameter

• target - The macro to call or asset to retrieve. lib://<libraryName>/macro/<macroName> style lib-URIs work, as do asset://<asset-hash> (as returned by the getImage() function). macros use a locationless-URI macro:macroName@macroLocation
• options - A javascript object mapping optional arguments to values. Notable options are below
• method - HTTP Method to emulate. GET for assets/library resources, POST for macro calls.
• body - The body of the request to send. Can be a promise which returns a body. Lazily coerced to string
• headers - A javascript ojbect containing request headers to include

Like the native fetch API in javascript, you can also create a new Request() object and pass that in to fetch(). Internally, the fetch() wrapper does this for you. It then calls XMLHttpRequest() and returns a promise which resolves when the XMLHttpRequest() finishes.

See XMLHttpRequest() for handling macro headers and macro special variables.

See Also

XMLHttpRequest
Fetch API at MDN