framework/js/dist-typings/common/utils/SubtreeRetainer.d.ts
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Includes transpiled JS/TS, and Typescript declaration files (typings).

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TypeScript

/**
* The `SubtreeRetainer` class keeps track of a number of pieces of data,
* comparing the values of these pieces at every iteration.
*
* This is useful for preventing redraws to relatively static (or huge)
* components whose VDOM only depends on very few values, when none of them
* have changed.
*
* @example
* // Check two callbacks for changes on each update
* this.subtree = new SubtreeRetainer(
* () => this.attrs.post.freshness,
* () => this.showing
* );
*
* // Add more callbacks to be checked for updates
* this.subtree.check(() => this.attrs.user.freshness);
*
* // In a component's onbeforeupdate() method:
* return this.subtree.needsRebuild()
*
* @see https://mithril.js.org/lifecycle-methods.html#onbeforeupdate
*/
export default class SubtreeRetainer {
/**
* @param {...callbacks} callbacks Functions returning data to keep track of.
*/
constructor(...callbacks: any[]);
callbacks: any[];
data: {};
/**
* Return whether any data has changed since the last check.
* If so, Mithril needs to re-diff the vnode and its children.
*
* @return {boolean}
* @public
*/
public needsRebuild(): boolean;
/**
* Add another callback to be checked.
*
* @param {...Function} callbacks
* @public
*/
public check(...callbacks: Function[]): void;
/**
* Invalidate the subtree, forcing it to be rerendered.
*
* @public
*/
public invalidate(): void;
}