Inserts the given node into the Template, optionally before the given refNode. In addition to inserting the node into the Template, the Template part indices are updated to match the mutated Template DOM.
Removes the list of nodes from a Template safely. In addition to removing nodes from the Template, the Template part indices are updated to match the mutated Template DOM.
As the template is walked the removal state is tracked and part indices are adjusted as needed.
div div#1 (remove) <-- start removing (removing node is div#1) div div#2 (remove) <-- continue removing (removing node is still div#1) div div <-- stop removing since previous sibling is the removing node (div#1, removed 4 nodes)
Extension to the standard render
method which supports rendering
to ShadowRoots when the ShadyDOM (https://github.com/webcomponents/shadydom)
and ShadyCSS (https://github.com/webcomponents/shadycss) polyfills are used
or when the webcomponentsjs
(https://github.com/webcomponents/webcomponentsjs) polyfill is used.
Adds a scopeName
option which is used to scope element DOM and stylesheets
when native ShadowDOM is unavailable. The scopeName
will be added to
the class attribute of all rendered DOM. In addition, any style elements will
be automatically re-written with this scopeName
selector and moved out
of the rendered DOM and into the document <head>
.
It is common to use this render method in conjunction with a custom element
which renders a shadowRoot. When this is done, typically the element's
localName
should be used as the scopeName
.
In addition to DOM scoping, ShadyCSS also supports a basic shim for css
custom properties (needed only on older browsers like IE11) and a shim for
a deprecated feature called @apply
that supports applying a set of css
custom properties to a given location.
Usage considerations:
Part values in <style>
elements are only applied the first time a given
scopeName
renders. Subsequent changes to parts in style elements will have
no effect. Because of this, parts in style elements should only be used for
values that will never change, for example parts that set scope-wide theme
values or parts which render shared style elements.
Note, due to a limitation of the ShadyDOM polyfill, rendering in a
custom element's constructor
is not supported. Instead rendering should
either done asynchronously, for example at microtask timing (for example
Promise.resolve()
), or be deferred until the first time the element's
connectedCallback
runs.
Usage considerations when using shimmed custom properties or @apply
:
Whenever any dynamic changes are made which affect
css custom properties, ShadyCSS.styleElement(element)
must be called
to update the element. There are two cases when this is needed:
(1) the element is connected to a new parent, (2) a class is added to the
element that causes it to match different custom properties.
To address the first case when rendering a custom element, styleElement
should be called in the element's connectedCallback
.
Shimmed custom properties may only be defined either for an entire
shadowRoot (for example, in a :host
rule) or via a rule that directly
matches an element with a shadowRoot. In other words, instead of flowing from
parent to child as do native css custom properties, shimmed custom properties
flow only from shadowRoots to nested shadowRoots.
When using @apply
mixing css shorthand property names with
non-shorthand names (for example border
and border-width
) is not
supported.
Generated using TypeDoc
Module to add shady DOM/shady CSS polyfill support to lit-html template rendering. See the render method for details.