epos

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Frame API ​

The Frame API lets you manage background frames — hidden iframes running in the background of your extension.
Frames are useful for running isolated scripts, maintaining hidden state, or hosting background UI such as invisible canvases or offscreen views.

epos.frame.open ​

Opens (or reuses) a background frame.
Each frame has a unique name, and if a frame with the same name already exists, it won’t be created again.

ts
epos.frame.open(name: string, url: string, attributes?: Record<string, unknown>): Promise<void>
js
await epos.frame.open('preview', 'frame:./preview.html')

epos.frame.close ​

Closes a background frame by name.

Usage

ts
epos.frame.close(name: string): Promise<void>

Example

js
await epos.frame.close('preview')

epos.frame.exists ​

Checks whether a background frame with the given name currently exists.

Usage

ts
epos.frame.exists(name: string): Promise<boolean>

Example

js
if (await epos.frame.exists('preview')) {
  console.log('Preview frame is active')
}

epos.frame.list ​

Returns a list of all currently open background frames, including their names and URLs.

Usage

ts
epos.frame.list(): Promise<{ name: string; url: string }[]>

Example

js
const frames = await epos.frame.list()
console.table(frames)

Frames opened through this API stay active in the background until explicitly closed. They can communicate with other parts of your extension using the Bus API.