addon.tab

Available in userscripts ✔️
Available in popup scripts
Required manifest permissions None

Description

Allows addon userscripts to get information about the tab they’re currently running on.

Examples

Using addon.tab.waitForElement

We can use addon.tab.waitForElement with {"markAsSeen": true} inside a while(true) loop to store the IDs of all comments in the page.
Using addon.tab.waitForElement, we don’t need to have code that waits until comments have loaded. This way, we also store the IDs of newly posted comments and new loaded comments when the user clicks “load more comments”.

const commentIds = [];
while (true) {
  const comment = await addon.tab.waitForElement("div.comment", {
      markAsSeen: true,
  });
  commentIds.push(comment.id);
}

Using addon.tab.displayNoneWhileDisabled (dynamicDisable)

We use addon.tab.displayNoneWhileDisabled to hide an image when the addon gets disabled.
We create a button to hide the image when clicked, and the image succesfully gets hidden, even if the addon is enabled.
We also set the display CSS property of the image to flex when visible, even tho that is not the default value for images.

  /* userscript.js */
  const img = document.createElement("img");
  img.classList.add("sa-example-img");
  addon.tab.displayNoneWhileDisabled(img, { display: "flex" });
  const btn = document.createElement("btn");
  btn.onclick = () => {
    // We want to hide the image
    // We cannot do `img.style.display = "none"` because we
    // used displayNoneWhileDisabled with the same element
    img.classList.add("sa-example-img-hide");
  };
/* userstyle.css */
.sa-example-img {
  display: flex;
}
.sa-example-img-hide {
  /* We want to hide the image if the button was clicked, 
  even if the addon is enabled */
  display: none !important;
}

Reacting to URL dynamically changed

addon.tab.addEventListener("urlChange", function(event) {
  console.log(`URL changed! It was previously ${event.detail.oldUrl}, it's now ${event.detail.newUrl}`);
});

Sub-APIs

addon.tab.traps

Allows addons to get direct references to objects, which are particularly useful for enhancing the editor, like the Scratch VM or the Blockly instance.

addon.tab.redux

Allows addons to get and modify Redux state, which is useful for addons that modify scratch-www pages and the editor.

Properties

addon.tab.clientVersion

Value "scratch-www" | "scratchr2"
Nullable Yes

The Scratch client for the current tab (scratch-www or scratchr2).
The Scratch community website has 2 working clients used throughout the site.
scratch-www is React/Redux based and client side rendered. This client is the one used in the homepage.
scratchr2 is Django/jQuery/Backbone.js based and mostly server side rendered. This client is the one used in profile pages.

addon.tab.editorMode

Value "projectpage" | "editor" | "fullscreen" | "embed"
Nullable Yes

The current viewing mode for the project (projectpage, editor, fullscreen or embed).
Will be null if the current tab is not a project.

addon.tab.direction

Value "ltr" | "rtl"
Nullable No

The writing direction for the language of the Scratch website.

Methods

addon.tab.waitForElement

Parameter Type Required Description
selector String Yes One or more selectors to match. Same parameter as document.querySelector.
options Object No
Property Type Required Default Description
markAsSeen Boolean No false Whether it should mark resolved elements to be skipped next time or not.
condition Function No () => true A function that returns whether to resolve the selector or not. No arguments are passed.
reduxCondition Function No () => true A function that returns whether to resolve the selector or not. addon.tab.redux is passed as an argument.
reduxEvents String[] No [] An array of Redux events that must be dispatched before resolving the selector.
Return value Promise<HTMLElement>

Waits until an element exists, then returns the element.
Internally, a MutationObserver that reacts to any DOM tree change is used. This observer does not react to attribute-only DOM updates.
Option markAsSeen should be set to true if you’re using this method inside a while(true) loop.
Options condition, reduxCondition and reduxEvents should be used as optimizations, in order to avoid multiple calls to document.querySelector when it’s guaranteed the element will not exist yet.

addon.tab.displayNoneWhileDisabled

Parameter Type Required Description
element HTMLElement Yes Element to hide
options Object No
Property Type Required Default Description
display String No "" The display CSS value to use when the addon is enabled.

Hides the given element with display: none when the addon is disabled, until it is reenabled.
If the intended display CSS property value for the provided element when visible is not the default value for the type of provided element (for example, block for divs and inline for spans), you should provide that value inside the options parameter.
If you want to manually hide the element in situations where the addon is enabled, you should use a dedicated class name for that, instead of manually setting el.style.display = "none";. Use a class name selector in a userstyle to set display: none !important; on the element.

addon.tab.copyImage

Required manifest permissions clipboardWrite
Parameter Type Required Description
dataURL String Yes Data URL of a PNG image.
Return value Promise<void>
Promise rejects if Image could not be copied.

Copies a PNG image to the clipboard.
Only run this in response of the user explicitly pressing Ctrl+C.
Internally uses browser.clipboard.setImageData in Firefox and navigator.clipboard.write in Chrome.

addon.tab.scratchClass

Parameter Type Required Description
unhashedClassName String Min 1 One or many unhashed Scratch stylesheet class names, as one argument each.
opts Object No
Property Type Required Description
others String | String[] Yes Non-Scratch class(es) to merge
Return value String

Gets the hashed class name for a Scratch stylesheet class name.

addon.tab.scratchMessage

Parameter Type Required Description
key String Yes The Scratch translation key.
Return value String | ""

Gets Scratch translation from the current Scratch tab.
Note that these are Scratch locales, not Scratch Addons locales.
If the message isn’t found, "" is returned and a warning is logged in the console.
Internally uses window.django.gettext or window._messages.

addon.tab.appendToSharedSpace

See addon.tab.appendToSharedSpace.

addon.tab.createBlockContextMenu

Parameter Type Required Description
blockContextMenuCallback Function Yes Returns new menu items.
Parameter Type Description
items Object[] The items added by vanilla code or other addons.
Property Type Description
enabled Boolean Whether the item is enabled or not.
text String The context menu item label.
callback Function The function that is called when the item is clicked.
separator Boolean Whether to add a separator above the item or not.
block Object The targeted block, if any.
conditions Object No Show the context menu item in various locations.
Property Type Required Default Description
workspace Boolean No false The workspace context menu.
blocks Boolean No false The block context menu outside the flyout.
flyout Boolean No false The block context menu inside the flyout.
comments Boolean No false The context menu on comments.

Adds a context menu item for any of the context menus in the code editor.

addon.tab.createEditorContextMenu

Documentation for this is a WIP. Not all possible types are listed for some settings.

Parameter Type Required Description
callback Function Yes The function that is executed when the item is clicked.
Parameter Type Description
context Object The context for the action.
Property Type Description
type String The type of the context menu. Possible values: "sprite", "costume", "sound"
menuItem HTMLElement The item element.
target HTMLElement The element that this context menu is selecting.
index Number The index, if applicable.
options Object No (but then it must be returned in `callback`)
Property Type Required Default Description
className String Yes The class name to add to the item.
types String[] No All possible values Which types of context menu the item should be added to. Possible values: "sprite", "costume", "sound"
position String Yes The shared space inside of the context menu that the item should be added to. Uses `addon.tab.appendToSharedSpace` internally. Possible values: "assetContextMenuAfterExport", "assetContextMenuAfterDelete", "monitor"
order Number Yes The order of the item within its shared space in relation to other items.
label String Yes The label for the item.
border Boolean No false Whether to add a border to the top of the item or not.
dangerous Boolean No false Whether to display the item as "dangerous" (orange-colored) or not.
condition Function No true A function that determines if the item should be shown.
Parameter Type Description
context Object The context for the action.
Property Type Description
type String The type of the context menu. Possible values: "sprite", "costume", "sound"
menuItem HTMLElement The item element.
target HTMLElement The element that this context menu is selecting.
index Number The index, if applicable.

Adds a context menu item for any of the non-Blockly context menus, such as the context menu for the sprites list.

addon.tab.addBlock

Do not use this unless you are adding blocks to the debugger addon.

Parameter Type Required Description
proccode String Yes The name that will be used to refer to the block internally. Must specify inputs on the block (if any) using %s (string), %n (number-only), and %b (boolean).
blockData Object Yes
Property Type Required Default Description
args String[] Yes A list of names that will be used to refer to the block's inputs in the callback. If there are no inputs, use an empty array.
displayName String no The value of `proccode` The name that will be displayed on the block to the user. Must also include block input syntax.
callback Function Yes The function that will execute when the block runs.
Parameter Description
args An object containing the values that are entered into the block inputs. The keys correpond to the `args` property specified earlier.
thread A reference to the thread that this block is running in.
hidden Boolean No false Whether the block should appear in the flyout or not. This does not affect the workspace.

Adds a new block to the Debugger category in the block palette.

addon.tab.removeBlock

Parameter Type Required Description
proccode String Yes The `proccode` value of the block to remove

Removes a block that was previously added to the Debugger category in the block palette.

addon.tab.loadScript

In most cases, you should use the userscripts property of the addon manifest instead.

Parameter Type Required Description
path String Yes The path pointing to the script.
Return value Promise

Runs the specified script file.

addon.tab.loadWorker

Parameter Type Required Description
path String Yes The path pointing to the worker.
Return value Promise<Worker>

Loads the specified Web Worker.

Events

urlChange

Event detail property Type Description
oldUrl String The URL before it was dynamically changed
newUrl String The new current URL value

Fires when Scratch dynamically changes the URL of the page.
This happens when going inside/outside the editor, or switching tabs in scratch-www studio pages.
This will not fire if location.hash changed.


Section Pages


Last updated at 16 January 2022 by lisa-wolfgang on commit c19985d. Improve this page.