web-vitals
Version:
Easily measure performance metrics in JavaScript
56 lines (55 loc) • 1.98 kB
TypeScript
import type { LoadState, Metric } from './base.js';
/**
* A CLS-specific version of the Metric object.
*/
export interface CLSMetric extends Metric {
name: 'CLS';
entries: LayoutShift[];
}
/**
* An object containing potentially-helpful debugging information that
* can be sent along with the CLS value for the current page visit in order
* to help identify issues happening to real-users in the field.
*/
export interface CLSAttribution {
/**
* A selector identifying the first element (in document order) that
* shifted when the single largest layout shift contributing to the page's
* CLS score occurred.
*/
largestShiftTarget?: string;
/**
* The time when the single largest layout shift contributing to the page's
* CLS score occurred.
*/
largestShiftTime?: DOMHighResTimeStamp;
/**
* The layout shift score of the single largest layout shift contributing to
* the page's CLS score.
*/
largestShiftValue?: number;
/**
* The `LayoutShiftEntry` representing the single largest layout shift
* contributing to the page's CLS score. (Useful when you need more than just
* `largestShiftTarget`, `largestShiftTime`, and `largestShiftValue`).
*/
largestShiftEntry?: LayoutShift;
/**
* The first element source (in document order) among the `sources` list
* of the `largestShiftEntry` object. (Also useful when you need more than
* just `largestShiftTarget`, `largestShiftTime`, and `largestShiftValue`).
*/
largestShiftSource?: LayoutShiftAttribution;
/**
* The loading state of the document at the time when the largest layout
* shift contribution to the page's CLS score occurred (see `LoadState`
* for details).
*/
loadState?: LoadState;
}
/**
* A CLS-specific version of the Metric object with attribution.
*/
export interface CLSMetricWithAttribution extends CLSMetric {
attribution: CLSAttribution;
}