web-vitals/dist/modules/lib/initMetric.js

Easily measure performance metrics in JavaScript

/*
 * Copyright 2020 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 { getBFCacheRestoreTime } from './bfcache.js';
import { generateUniqueID } from './generateUniqueID.js';
import { getActivationStart } from './getActivationStart.js';
import { getNavigationEntry } from './getNavigationEntry.js';
export const initMetric = (name, value) => {
    const navEntry = getNavigationEntry();
    let navigationType = 'navigate';
    if (getBFCacheRestoreTime() >= 0) {
        navigationType = 'back-forward-cache';
    }
    else if (navEntry) {
        if (document.prerendering || getActivationStart() > 0) {
            navigationType = 'prerender';
        }
        else {
            navigationType =
                navEntry.type.replace(/_/g, '-');
        }
    }
    return {
        name,
        value: typeof value === 'undefined' ? -1 : value,
        rating: 'good',
        delta: 0,
        entries: [],
        id: generateUniqueID(),
        navigationType,
    };
};