annotation WebExtension::Chainable

Overview

When a Crystal instance method is annotated with Chainable, it means that the method will return the instance itself instead of a JSC::JSValue. It does not matter what type of data the method returns, it will always return the current instance which call the method.

• extension.cr

require 'alizarin'
include WebExtension
class File #here we do not have to construct a new class from scratch, just extend existing one.
  def initialize(params : [] of JSCObject | JSCFunction | JSCPrimative)
      super(params.first.to_s)
  end

  @content = ""

  @[JSCInstanceMethod]
  @[Chainable]
  def read(p)
    self.seek(0)
    @content = self.gets_to_end
  end

  @[JSCInstanceMethod]
  def content(p)
    @content
  end
end

initialize_extension do
    JSCContext.set_value "File", register_class(File)
end

• index.js

var file_content = new File("./LICENSE").read().content();
console.log(file_content);

Defined in:

components/web_extension/annotations.cr