HTMLSlotElement: assign() method
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2023.
The assign() method of the HTMLSlotElement interface sets the slot's manually assigned nodes to an ordered set of slottables. The manually assigned nodes set is initially empty until nodes are assigned using assign().
Note:
You cannot mix manually (imperative) and named (declarative, automatic) slot assignments. Therefore, for this method to work, the shadow tree needs to have been created with the slotAssignment: "manual" option.
Syntax
assign(node1)
assign(node1, node2)
assign(node1, node2, /* …, */ nodeN)
Parameters
Return value
None (undefined).
Exceptions
NotAllowedErrorDOMException-
Thrown when calling this method on an automatically assigned slot.
Examples
In the example below, the assign() method is used to display the correct tab in a tabbed application. The function is called and passed the panel to show, which is then assigned to the slot.
function UpdateDisplayTab(elem, tabIdx) {
const shadow = elem.shadowRoot;
const slot = shadow.querySelector("slot");
const panels = elem.querySelectorAll("tab-panel");
if (panels.length && tabIdx && tabIdx <= panels.length) {
slot.assign(panels[tabIdx - 1]);
} else {
slot.assign();
}
}
Specifications
| Specification |
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| HTML # dom-slot-assign |
Browser compatibility
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assign
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Legend
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- Full support
- Full support
- Partial support
- Partial support
- See implementation notes.
- Has more compatibility info.