web-vitals
Version:
Easily measure performance metrics in JavaScript
49 lines (48 loc) • 1.63 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.
*/
const getName = (node) => {
const name = node.nodeName;
return node.nodeType === 1
? name.toLowerCase()
: name.toUpperCase().replace(/^#/, '');
};
export const getSelector = (node, maxLen) => {
let sel = '';
try {
while (node && node.nodeType !== 9) {
const el = node;
const part = el.id
? '#' + el.id
: getName(el) +
(el.classList &&
el.classList.value &&
el.classList.value.trim() &&
el.classList.value.trim().length
? '.' + el.classList.value.trim().replace(/\s+/g, '.')
: '');
if (sel.length + part.length > (maxLen || 100) - 1)
return sel || part;
sel = sel ? part + '>' + sel : part;
if (el.id)
break;
node = el.parentNode;
}
}
catch (err) {
// Do nothing...
}
return sel;
};