web-vitals
Version:
Easily measure performance metrics in JavaScript
48 lines (47 loc) • 2.07 kB
JavaScript
/*
* Copyright 2022 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { getNavigationEntry } from './getNavigationEntry.js';
export const getLoadState = (timestamp) => {
if (document.readyState === 'loading') {
// If the `readyState` is 'loading' there's no need to look at timestamps
// since the timestamp has to be the current time or earlier.
return 'loading';
}
else {
const navigationEntry = getNavigationEntry();
if (navigationEntry) {
if (timestamp < navigationEntry.domInteractive) {
return 'loading';
}
else if (navigationEntry.domContentLoadedEventStart === 0 ||
timestamp < navigationEntry.domContentLoadedEventStart) {
// If the `domContentLoadedEventStart` timestamp has not yet been
// set, or if the given timestamp is less than that value.
return 'dom-interactive';
}
else if (navigationEntry.domComplete === 0 ||
timestamp < navigationEntry.domComplete) {
// If the `domComplete` timestamp has not yet been
// set, or if the given timestamp is less than that value.
return 'dom-content-loaded';
}
}
}
// If any of the above fail, default to loaded. This could really only
// happy if the browser doesn't support the performance timeline, which
// most likely means this code would never run anyway.
return 'complete';
};