Icard/angular-clarity-master(work.../node_modules/lit-html/development/directives/cache.js

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2024-07-16 14:55:36 +00:00
/**
* @license
* Copyright 2017 Google LLC
* SPDX-License-Identifier: BSD-3-Clause
*/
import { render, nothing, } from '../lit-html.js';
import { directive, Directive, } from '../directive.js';
import { clearPart, getCommittedValue, insertPart, isCompiledTemplateResult, isTemplateResult, setCommittedValue, } from '../directive-helpers.js';
/**
* The template strings array contents are not compatible between the two
* template result types as the compiled template contains a prepared string;
* only use the returned template strings array as a cache key.
*/
const getStringsFromTemplateResult = (result) => isCompiledTemplateResult(result) ? result['_$litType$'].h : result.strings;
class CacheDirective extends Directive {
constructor(partInfo) {
super(partInfo);
this._templateCache = new WeakMap();
}
render(v) {
// Return an array of the value to induce lit-html to create a ChildPart
// for the value that we can move into the cache.
return [v];
}
update(containerPart, [v]) {
const _valueKey = isTemplateResult(this._value)
? getStringsFromTemplateResult(this._value)
: null;
const vKey = isTemplateResult(v) ? getStringsFromTemplateResult(v) : null;
// If the previous value is a TemplateResult and the new value is not,
// or is a different Template as the previous value, move the child part
// into the cache.
if (_valueKey !== null && (vKey === null || _valueKey !== vKey)) {
// This is always an array because we return [v] in render()
const partValue = getCommittedValue(containerPart);
const childPart = partValue.pop();
let cachedContainerPart = this._templateCache.get(_valueKey);
if (cachedContainerPart === undefined) {
const fragment = document.createDocumentFragment();
cachedContainerPart = render(nothing, fragment);
cachedContainerPart.setConnected(false);
this._templateCache.set(_valueKey, cachedContainerPart);
}
// Move into cache
setCommittedValue(cachedContainerPart, [childPart]);
insertPart(cachedContainerPart, undefined, childPart);
}
// If the new value is a TemplateResult and the previous value is not,
// or is a different Template as the previous value, restore the child
// part from the cache.
if (vKey !== null) {
if (_valueKey === null || _valueKey !== vKey) {
const cachedContainerPart = this._templateCache.get(vKey);
if (cachedContainerPart !== undefined) {
// Move the cached part back into the container part value
const partValue = getCommittedValue(cachedContainerPart);
const cachedPart = partValue.pop();
// Move cached part back into DOM
clearPart(containerPart);
insertPart(containerPart, undefined, cachedPart);
setCommittedValue(containerPart, [cachedPart]);
}
}
// Because vKey is non null, v must be a TemplateResult.
this._value = v;
}
else {
this._value = undefined;
}
return this.render(v);
}
}
/**
* Enables fast switching between multiple templates by caching the DOM nodes
* and TemplateInstances produced by the templates.
*
* Example:
*
* ```js
* let checked = false;
*
* html`
* ${cache(checked ? html`input is checked` : html`input is not checked`)}
* `
* ```
*/
export const cache = directive(CacheDirective);
//# sourceMappingURL=cache.js.map