Application-Programming-Interface (API)

experimental

The Pear API enables applications to interact with Pear platform features.

Most application peer-to-peer functionality is provided by ecosystem modules rather than the API.

Platform APIs are unchangable. Compatiblity cannot break. So the Pear API surface aims to be (and remain) as small as possible.

`global.Pear`

The Pear Platform API is made available globally as Pear.

The Pear API is designed to be small and immutable.

Any future changes to the Pear API will be non-breaking additions.

`Pear.config <Object>`

Contains application configuration data.

`Pear.config.key <Object|null>`

The application key, null in development mode. The config.key object holds both Hexadecimal and Z-Base-32 encodings of the key, and is of the form { z32: <String>, hex: <String> },

`Pear.config.dev <Boolean>`

Application is local (loaded from disk).

Equivalent to pear.config.key === null.

`Pear.config.tier <String>`

Runtime scenario (dev, staging or production)

`Pear.config.storage <String>`

Application storage path

`Pear.config.name <String>`

Application name

`Pear.config.main <String>`

Application entry file

`Pear.config.channel <String|null>`

Application release/staging channel, null in development mode.

`Pear.config.options <Object>`

Configuration options. The pear configuration object as supplied via an applications package.json file.

References

Configuration

`Pear.config.env <Object>`

The environment variables that an application was started with, as key-value pairs in an object.

`Pear.config.cwd <String>`

The current working directory that an application was started from.

`Pear.config.flags <Object>`

Parsed command-line flag values as supplied when an application was started.

`Pear.config.tools <Boolean>`

Indicates whether or not Devtools is enabled.

`Pear.config.watch <Boolean>`

Indicates whether or not Watch-Reload functionality is enabled.

`Pear.config.storage <String>`

Application storage path.

`Pear.config.args <Array>`

Command-line application arguments passed like pear dev . --some arg.

`Pear.config.release <Number>`

The current release length as marked by the pear release command.

References

pear release

`Pear.config.link <String>`

The Pear link of an application. Takes the form pear://<key>/<data>.

In development, pear://dev/<data>.

References

`Pear.config.links <Object|Array>`

Holds trusted Pear application links and domains as specified in the links field inside package.json.

References

`Pear.config.linkData <String>`

Holds just the data portion of a Pear link.

The Pear link of an application. Takes the form pear://<key>/<data>.

In development, pear://dev/<data>.

References

`Pear.config.checkpoint <Any>`

Holds state as set by Pear.checkpoint(). When an application restarts it will hold the most recent value passed to Pear.checkpoint().

Stores state that will be available as Pear.config.checkpoint next time the application starts.

The Pear.config.checkpoint property immediately reflects the latest checkpoint.

The returned Promise will resolve once the checkpoint has been successfully stored.

References

Pear.checkpoint()

`Pear.config.release <Integer>`

Application release sequence integer, null in development mode.

`Pear.config.flags <Object>`

Parsed runtime flags. For internal/advanced use.

`Pear.checkpoint(<Any>) => Promise`

Stores state that will be available as Pear.config.checkpoint next time the application starts.

The Pear.config.checkpoint property immediately reflects the latest checkpoint.

The returned Promise will resolve once the checkpoint has been successfully stored.

References

Pear.config.checkpoint()

Pear.messages([ pattern ], [ listener ]) -> Iterable

A function which accepts a pattern object and returns an Iambus subscriber (which inherits from streamx Readable) which emits message objects matching a provided pattern object.

If no pattern object or an empty pattern object is provided all messages will be emitted. A pattern object is an object (typically) containing a subset of matching values for a given target object. Message objects can be user generated or platform generated.

The subscriber stream has a data event which can be listened to, it can also be consumed with for await and an listener function can be passed in addition to pattern (message(pattern, listener)) or as a single argument (messages(listener)) (indicateding a catch-all pattern).

A message object may have any properties. Platform-generated messages are given a type property.

Examples:

Listen for an internal platform message using a pattern object and listener function:

const { messages } = Pear

messages({ type: 'pear/wakeup' }, ({ data, link }) => {
  console.log('pear/wakeup', data, link)
})

Tiny utility module which logs all messages using for await:

const { messages } = Pear

for await (const message of messages()) {
  if (global.LOGBUS) console.log('BUS:', message)
}

Use message to create an application message:

const { message, messages } = Pear

const ctaClicks = message({ type: 'my-app/user-cta' })

ctaClicks.on('data', (msg) => { console.log('cta click', msg) })

// elsewhere
onUserClickCta((event, data) => {
  message({ type: 'my-app/user-cta', event, data })
})

`await Pear.message(<Object>)`

Send a message which will be:

const { message, messages } = Pear

async function logMessages () {
  for await (const message of messages()) console.log(message)
}

logMessages().catch(console.error)

let count = 0
do {
  await message({ type: 'tick', count })
  await new Promise((resolve) => setTimeout(resolve, 1000))
} while (count++ < 1000)

`Pear.preferences <Function|Object>`

User preferences management.

`for await (const [operation, key, value] of Pear.preferences())`

An async iterable that yields arrays containing operation <String>, key <String> and value <any>.

Watch for application updates. The operation may be set or del. In the case of del, value is always null.

`for await (const [key, value] of Pear.preferences.list())`

Iterate through all available application preferences.

`const success = await Pear.preferences.set(key, value)`

Set a preference. The promise resolves to a boolean indicating success when the operation is complete.

`const value = await Pear.preferences.get(key)`

Get a preference. The promise resolves with the value.

`const success = await Pear.preferences.del(key)`

Delete a preference. The promise resolves to a boolean indicating success when the operation is complete.

const { preferences } = Pear

async function logPrefUpdates () {
  for await (const [ operation, key, value ] of preferences()) console.table({ update: { operation, key, value }})
}

logPrefUpdates().catch(console.error)

`Pear.worker <Object>`

Pear Worker is used to spawn processes and facilitate communication between the parent and child processes in the Pear Runtime.

The spawned worker process inherits standard input, output, and error from the parent process.

A bidirectional pipe is also created which enables communication between the parent and worker process.

Reference counting is handled automatically to manage the sidecar lifecycle.

`const pipe = Pear.worker.run(link <String>, args <Array<String>>)`

Runs a Pear Worker by spawning a Pear Terminal Application process from the specified link parameter. The Worker uses the flags of the parent application but any application arguments must be passed using the args parameter, the args parameter also sets Pear.config.args. Returns a pipe (a streamx Duplex stream) for Worker communication.

`const pipe = Pear.worker.pipe()`

Returns the pipe (a streamx Duplex stream) created to the worker process.

`Pear.media <Object>`

Media interface

`const status = await Pear.media.status.microphone()`

Resolves to: <String>

If access to the microphone is available, resolved value will be 'granted'.

Any other string indicates lack of permission. Possible values are 'granted', 'not-determined', 'denied', 'restricted', 'unknown'.

`const status = await Pear.media.status.camera()`

Resolves to: <String>

If access to the camera is available, resolved value will be 'granted'.

Any other string indicates lack of permission. Possible values are 'granted', 'not-determined', 'denied', 'restricted', 'unknown'.

`const status = await Pear.media.status.screen()`

Resolves to: <String>

If access to the screen is available, resolved value will be 'granted'.

Any other string indicates lack of permission. Possible values are 'granted', 'not-determined', 'denied', 'restricted', 'unknown'.

`const success = await Pear.media.access.microphone()`

Resolves to: <Boolean>

Request access to the microphone. Resolves to true if permission is granted.

`const success = await Pear.media.access.camera()`

Resolves to: <Boolean>

Request access to the camera. Resolves to true if permission is granted.

`const success = await Pear.media.access.screen()`

Resolves to: <Boolean>

Request access to screen sharing. Resolves to true if permission is granted.

`const sources = await Pear.media.desktopSources(options <Object>)`

Captures available desktop sources. Resolves to an array of objects with shape { id <String>, name <String>, thumbnail <NativeImage>, display_id <String>, appIcon <NativeImage> }. The id is the window or screen identifier. The name is the window title or 'Screen <index>' in multiscreen scenarios or else Entire Screen. The display_id identifies the screen. The thumbnail is a scaled down screen capture of the window/screen.

Options

types <Array<String>> - Default: ['screen', 'window']. Filter by types. Types are 'screen' and 'window'.
thumbnailSize <Object> - Default: {width: 150, height: 150}. Set thumbnail scaling (pixels)
fetchWindowIcons <Boolean> - Default: false. Populate appIcon with Window icons, or else null.

References

win.getMediaSourceId()
view.getMediaSourceId()
self.getMediaSourceId()
parent.getMediaSourceId()
https://www.electronjs.org/docs/latest/api/desktop-capturer#desktopcapturergetsourcesoptions
https://www.electronjs.org/docs/latest/api/structures/desktop-capturer-source
<NativeImage>

`Pear.versions <Async Function>`

Function that returns a promise which resolves to a Pear versions object with the shape { fork <Integer>, length <Integer>, key <Buffer> }.

The key is a Buffer of the run key. The length is the size of the relevant Hypercore. The fork property is determined by data truncation.

These three properties together are a unique identifier for the entire state of both applications and the Pear platform.

`Pear.versions.platform { fork <Integer>, length <Integer>, key <Buffer> }`

The platform version.

`Pear.versions.app { fork <Integer>, length <Integer>, key <Buffer> }`

The application version.

`Pear.versions.runtimes { bare <Integer>, electron <Integer>, pear <Integer> }`

The versions of runtimes.

References

Pear.config.key

`Pear.teardown(fn <Async Function|Function>)`

May be called multiple times to register multiple teardown handlers.

Functions supplied to teardown will be executed in order of registration when an application begins to unload. Any promise returned from each supplied function will be waited upon until resolution before calling the next teardown handler.

Pear.reload()

Soft-restart Terminal applications (keeps I/O), refresh application in Desktop applications.

`Pear.restart()`

Restart the application.

`Pear.exit(code)`

Exits the process with the provided exit code.

`Pear.updates(listener <Async Function|Function>) => streamx.Readable`

The listener function is called for every incoming update with an update object of the form:

{
  type: 'pear/updates',
  version: { fork <Integer>, length <Integer>, key <String(hex)>,  } | null,
  app <Boolean>,
  diff <Array <String> >,
}

version is a Pear version object holding incoming version information
app indicates whether the update represents an application (true) or platform (false) update
diff requires --update-diffs flag (else null). An array of objects of form { type, key}.
- type <String> - Operation type update or delete
- key <String> - Drive key for a given updated file e.g. /path/to/file.txt

Also returns a streamx Readable) stream.

`Pear.wakeups(listener <Async Function|Function>) => streamx.Readable`

A wakeup occurs in the following cases:

when a trusted pear:// link is clicked and the application for that link is already open
when used with pear run --detached pear://<key>[/data]

The listener function is called for every incoming wakeup with a wakeup object of the form:

{
  type: 'pear/wakeup',
  link: <String>,
  linkData: <String>,
  fragment: <String>,
  entrypoint: <String>
}

link is the pear:// link for the application receiving the wakeup
linkData is everything after the key in the pear:// link - this would be pathname of a URL object but without the leading slash (/). Given pear://8ts9yz9dtucxzwbxafygnjasqe9ti3dt3w7rm6sbiu8prmidacao/some/more/stuff the data string would hold some/more/stuff.
fragment is the fragment part of pear://link#fragment (location hash without the # prefix).
entrypoint includes entrypoint of pear://link/some/entry/point (URL pathname).

Also returns a streamx Readable) stream.

`const win = new Pear.Window(entry <String>, options <Object>)`

Desktop Applications only.

Create a new Window instance.

Options

show <Boolean> Default: true - show the window as soon as it has been opened
x <Integer> - the horizontal position of left side of the window (pixels)
y <Integer> - vertical window position (pixels)
width <Integer> - the width of the window (pixels)
height <Integer> - the height of the window (pixels)
animate <Boolean> Default: false - animate the dimensional change. MacOS only, ignored on other OS's.
center <Boolean - center the window upon opening
minWidth <Integer> - window minimum width (pixels)
minHeight <Integer> - window minimum height (pixels)
maxWidth <Integer> - window maximum width (pixels)
maxHeight <Integer> - window maximum height (pixels)
resizable <Boolean> - window resizability
movable <Boolean> - window movability
minimizable <Boolean> - window minimizability
maximizable <Boolean> - window maximizability
closable <Boolean> - window closability
focusable <Boolean> - window focusability
alwaysOnTop <Boolean> - Set window to always be on top
fullscreen <Boolean> - Set window to fullscreen upon open
kiosk <Boolean> - Set window to enter kiosk mode upon open
autoHideMenuBar <Boolean> - Hide menu bar unless Alt key is pressed (Linux, Windows)
hasShadow <Boolean> - Set window shadow
opacity <Number> - Set window opacity (0.0 - 1.0) (Windows, macOS)
transparent <Boolean> - Set window transparency
backgroundColor <String> Default: '#FFF' - window default background color. Hex, RGB, RGBA, HSL HSLA, CSS color

`win.on[ce]('message', (...args) => { })`

`for await (const [ ...args ] of win)`

Receive a message from the window. The received args array is deserialized via JSON.parse.

References

win.send()

`const success = await win.open(options <Object>)`

Resolves to: <Boolean>

Open the window.

Options

show Default: true - show the window as soon as it has been opened
x <Integer> - the horizontal position of left side of the window (pixels)
y <Integer> - vertical window position (pixels)
width <Integer> - the width of the window (pixels)
height <Integer> - the height of the window (pixels)
animate <Boolean> Default: false - animate the dimensional change. MacOS only, ignored on other OS's.
center <Boolean - center the window upon opening
minWidth <Integer> - window minimum width (pixels)
minHeight <Integer> - window minimum height (pixels)
maxWidth <Integer> - window maximum width (pixels)
maxHeight <Integer> - window maximum height (pixels)
resizable <Boolean> - window resizability
movable <Boolean> - window movability
minimizable <Boolean> - window minimizability
maximizable <Boolean> - window maximizability
closable <Boolean> - window closability
focusable <Boolean> - window focusability
alwaysOnTop <Boolean> - Set window to always be on top
fullscreen <Boolean> - Set window to fullscreen upon open
kiosk <Boolean> - Set window to enter kiosk mode upon open
autoHideMenuBar <Boolean> - Hide menu bar unless Alt key is pressed (Linux, Windows)
hasShadow <Boolean> - Set window shadow
opacity <Number> - Set window opacity (0.0 - 1.0) (Windows, macOS)
transparent <Boolean> - Set window transparency
backgroundColor <String> Default: '#FFF' - window default background color. Hex, RGB, RGBA, HSL HSLA, CSS color

`const success = await win.close()`

Resolves to: <Boolean>

Close the window.

`const success = await win.show()`

Resolves to: <Boolean>

Show the window.

`const success = await win.hide()`

Resolves to: <Boolean>

Hide the window.

`const success = await win.focus()`

Resolves to: <Boolean>

Focus the window.

`const success = await win.blur()`

Resolves to: <Boolean>

Blur the window.

`const success = await win.minimize()`

Resolves to: <Boolean>

Minimize the window.

`const success = await win.maximize()`

Resolves to: <Boolean>

Maximize the window.

`const success = await win.restore()`

Resolves to: <Boolean>

Unmaximize/unminimize the window if it is currently maximized/minimized.

`await win.send(...args)`

Send arguments to the window. They will be serialized with JSON.stringify.

`const sourceId = await win.getMediaSourceId()`

Resolves to: <String>

Correlates to the id property of objects in the array returned from Pear.media.desktopSources.

References

Pear.media.desktopSources
https://www.electronjs.org/docs/latest/api/browser-window#wingetmediasourceid

`const dimensions = await win.dimensions()`

Resolves to: {x <Integer>, y <Integer>, width <Integer>, height <Integer>} | null.

The height, width, horizontal (x), vertical (y) position of the window relative to the screen.

All units ar (pixels)

If the window is closed this will resolve to null.

References

await win.dimensions(options)

`await win.dimensions(options <Object>)`

const win = new Pear.Window('./some.html', {
  x: 10,
  y: 450,
  width: 300,
  height: 350
})

await win.open()
await new Promise((resolve) => setTimeout(resolve, 1000))

await win.dimensions({
  x: 20,
  y: 50,
  width: 550,
  height: 300,
  animate: true // only has an effect on macOS
})

Sets the dimensions of the window.

Options

x <Integer> - the horizontal position of left side of the window (pixels)
y <Integer> - the vertical position of the top of the window (pixels)
width <Integer> - the width of the window (pixels)
height <Integer> - the height of the window (pixels)
animate <Boolean> Default: false - animate the dimensional change. MacOS only, ignored on other OS's.
position <String> - may be 'center' to set the window in the center of the screen or else undefined.

References

const dimensions = await win.dimensions()

`const visible = await win.isVisible()`

Resolves to: <Boolean>

Whether the window is visible.

`const minimized = await win.isMinimized()`

Resolves to: <Boolean>

Whether the window is minimized.

`const maximized = await win.isMaximized()`

Resolves to: <Boolean>

Whether the window is maximized.

`const closed = await win.isClosed()`

Resolves to: <Boolean>

Whether the window is closed.

`const closed = await win.isClosed()`

Resolves to: <Boolean>

Whether the window is closed.

`const view = new Pear.View(options <Object>)`

Desktop Applications only.

Create a new View instance. Views provide isolated content views. Frameless, chromeless windows that can be embedded inside other windows and views.

Options

x <Integer> - the horizontal position of left side of the view (pixels)
y <Integer> - vertical view position (pixels)
width <Integer> - the width of the view (pixels)
height <Integer> - the height of the view (pixels)
backgroundColor <String> Default: '#FFF' - view default background color. Hex, RGB, RGBA, HSL HSLA, CSS color
autoresize <Object> Default { width=true, height=true, vertical=false, horizontal=false } - dimensions for the view to autoresize alongside. For example, if width is true and the view container increases/decreases in width, the view will increase/decrease in width at the same rate.

References

https://www.electronjs.org/docs/latest/api/browser-view#viewsetautoresizeoptions-experimental
https://www.electronjs.org/docs/latest/api/browser-view#viewsetbackgroundcolorcolor-experimental

`view.on[ce]('message', (...args) => { })`

`for await (const [ ...args ] of view)`

Receive a message from the view. The received args array is deserialized via JSON.parse.

References

view.send()

`const success = await view.open(options <Object>)`

Resolves to: <Boolean>

Open the view.

Options

x <Integer> - the horizontal position of left side of the view (pixels)
y <Integer> - vertical view position (pixels)
width <Integer> - the width of the view (pixels)
height <Integer> - the height of the view (pixels)
backgroundColor <String> Default: '#FFF' - view default background color. Hex, RGB, RGBA, HSL HSLA, CSS color
autoresize <Object> Default { width=true, height=true, vertical=false, horizontal=false } - dimensions for the view to autoresize alongside. For example, if width is true and the view container increases/decreases in width, the view will increase/decrease in width at the same rate.

`const success = await view.close()`

Resolves to: <Boolean>

Close the view.

`const success = await view.show()`

Resolves to: <Boolean>

Show the view.

`const success = await view.hide()`

Resolves to: <Boolean>

Hide the view.

`const success = await view.focus()`

Resolves to: <Boolean>

Focus the view.

`const success = await view.blur()`

Resolves to: <Boolean>

Blur the view.

`await view.send(...args)`

Send arguments to the view. They will be serialized with JSON.stringify.

`const sourceId = await view.getMediaSourceId()`

Resolves to: <String>

Supplies the id property of objects in the array returned from Pear.media.desktopSources.

References

Pear.media.desktopSources
https://www.electronjs.org/docs/latest/api/browser-window#wingetmediasourceid

`const dimensions = await view.dimensions()`

Resolves to: {x <Integer>, y <Integer>, width <Integer>, height <Integer>} | null.

The height, width, horizontal (x), vertical (y) position of the window relative to the screen.

All units ar (pixels)

If the Window is closed this will resolve to null.

References

await view.dimensions(options)

`await view.dimensions(options <Object>)`

const view = new Pear.View('./some.html', {
  x: 10,
  y: 450,
  width: 300,
  height: 350
})

await view.open()
await new Promise((resolve) => setTimeout(resolve, 1000))

await view.dimensions({
  x: 20,
  y: 50,
  width: 550,
  height: 300
})

Sets the dimensions of the view.

Options

x <Integer> - the horizontal position of left side of the window (pixels)
y <Integer> - the vertical position of the top of the window (pixels)
width <Integer> - the width of the window (pixels)
height <Integer> - the height of the window (pixels)

References

const dimensions = await view.dimensions()

`const visible = await view.isVisible()`

Resolves to: <Boolean>

Whether the view is visible.

`const closed = await view.isClosed()`

Resolves to: <Boolean>

Whether the view is closed.

`const { self } = Pear.Window` `const { self } = Pear.View`

`const success = await self.focus()`

Resolves to: <Boolean>

Focus current view or window.

`const success = await self.blur()`

Resolves to: <Boolean>

Blur current view or window.

`const success = await self.show()`

Resolves to: <Boolean>

Show current view or window.

`const success = await self.hide()`

Resolves to: <Boolean>

Hide current view or window.

`const sourceId = await self.getMediaSourceId()`

Get the sourceId of the current window or view.

References

win.getMediaSourceId()

`const success = await self.minimize()`

Resolves to: <Boolean>

Minimize current window.

Throws a TypeError if self is a view.

`const success = await self.maximize()`

Resolves to: <Boolean>

Maximize current window.

Throws a TypeError if self is a view.

`const success = await self.restore()`

Resolves to: <Boolean>

Unmaximize/unminimize the current window if it is currently maximized/minimized.

Throws a TypeError if self is a view.

`const success = await self.close()`

Resolves to: <Boolean>

Closes the current view or window.

`const isVisible = await self.isVisible()`

Resolves to: <Boolean>

Whether the current window or view is visible.

`const isMaximized = await self.isMaximized()`

Resolves to: <Boolean>

Whether the current window is maximized. Throws a TypeError if self is a view.

`const isMinimized = await self.isMinimized()`

Resolves to: <Boolean>

Whether the current window is minmized. Throws a TypeError if self is a view.

`const { parent } = Pear.Window` `const { parent } = Pear.View`

`parent.on[ce]('message', (...args) => { })`

`for await (const [ ...args ] of parent)`

Receive a message from the parent window or view. The received args array is deserialized via JSON.parse.

`await parent.send(...args)`

Send arguments to the parent view or window. They will be serialized with JSON.stringify.

`const success = await parent.focus()`

Resolves to: <Boolean>

Focus parent view or window.

`const success = await parent.blur()`

Resolves to: <Boolean>

Blur parent view or window.

`const success = await parent.show()`

Resolves to: <Boolean>

Show parent view or window.

`const success = await parent.hide()`

Resolves to: <Boolean>

Hide parent view or window.

`const sourceId = await parent.getMediaSourceId()`

Get the sourceId of the parent window or view.

References

win.getMediaSourceId()

`const success = await parent.minimize()`

Resolves to: <Boolean>

Minimize parent window.

Throws a TypeError if parent is a view.

`const success = await parent.maximize()`

Resolves to: <Boolean>

Maximize parent window.

Throws a TypeError if parent is a view.

`const success = await parent.restore()`

Resolves to: <Boolean>

Unmaximize/unminimize the parent window if it is currently maximized/minimized.

Throws a TypeError if parent is a view.

`const success = await parent.close()`

Resolves to: <Boolean>

Closes the parent view or window.

`const isVisible = await parent.isVisible()`

Resolves to: <Boolean>

Whether the parent window or view is visible.

`const isMaximized = await parent.isMaximized()`

Resolves to: <Boolean>

Whether the parent window is maximized. Throws a TypeError if parent is a view.

`const isMinimized = await parent.isMinimized()`

Resolves to: <Boolean>

Whether the parent window is minmized. Throws a TypeError if parent is a view.

Web APIs

Most Web APIs will work as-is.

This section details deviations in behavior from and notable aspects of Web APIs as they relate to Pear.

`window.open`

The window.open Web API function will ignore all arguments except for the URL parameter.

In browsers, window.open opens a new browser window. The opened window belongs to the same browser from which window.open is called.

In Pear, window.open loads the URL in the default system browser. It does not create a new application window (use Pear.Window to create application windows).

Therefore Pear's window.open only supports a single url argument. The target and windowFeatures parameters that browsers support are discarded.

Scripts and Modules

Like browsers, there is no support for CommonJS (e.g. the require function as used by Node.js is not supported in Pear Applications).

Like browsers, there is support for native EcmaScript Modules (ESM). A JavaScript Script has no module capabilities. A JavaScript Module has ESM capabilities.

Use <script type="module" src="path/to/my-file.js"> to load a JavaScript Module.

Use <script src="path/to/my-file.js"> to load a JavaScript Script.

Last updated 1 month ago