40 lines
1.5 KiB
JavaScript
40 lines
1.5 KiB
JavaScript
import { isBot } from '../../shared/lib/router/utils/is-bot';
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import { addBasePath } from '../add-base-path';
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export function isExternalURL(url) {
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return url.origin !== window.location.origin;
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}
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/**
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* Given a link href, constructs the URL that should be prefetched. Returns null
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* in cases where prefetching should be disabled, like external URLs, or
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* during development.
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* @param href The href passed to <Link>, router.prefetch(), or similar
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* @returns A URL object to prefetch, or null if prefetching should be disabled
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*/ export function createPrefetchURL(href) {
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// Don't prefetch for bots as they don't navigate.
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if (isBot(window.navigator.userAgent)) {
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return null;
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}
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let url;
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try {
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url = new URL(addBasePath(href), window.location.href);
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} catch (_) {
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// TODO: Does this need to throw or can we just console.error instead? Does
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// anyone rely on this throwing? (Seems unlikely.)
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throw Object.defineProperty(new Error(`Cannot prefetch '${href}' because it cannot be converted to a URL.`), "__NEXT_ERROR_CODE", {
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value: "E234",
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enumerable: false,
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configurable: true
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});
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}
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// Don't prefetch during development (improves compilation performance)
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if (process.env.NODE_ENV === 'development') {
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return null;
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}
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// External urls can't be prefetched in the same way.
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if (isExternalURL(url)) {
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return null;
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}
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return url;
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}
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//# sourceMappingURL=app-router-utils.js.map
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