84 lines
2.7 KiB
JavaScript
84 lines
2.7 KiB
JavaScript
const scriptKeys = new Set();
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export function onUpdate() {
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// determine if this is an initial request
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let initialRequest = scriptKeys.size === 0;
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// iterate over all script elements in document
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const scripts = document.getElementsByTagName('script');
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for (const script of Array.from(scripts)) {
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// only process scripts that include a data-reload attribute
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if (script.hasAttribute('data-reload')) {
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let key = getKey(script);
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if (!initialRequest) {
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// reload the script if data-reload is "always" or "true"... or if the script has not been loaded previously and data-reload is "once"
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let dataReload = script.getAttribute('data-reload');
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if ((dataReload === 'always' || dataReload === 'true') || (!scriptKeys.has(key) && dataReload == 'once')) {
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reloadScript(script);
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}
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}
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// save the script key
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if (!scriptKeys.has(key)) {
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scriptKeys.add(key);
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}
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}
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}
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}
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function getKey(script) {
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if (script.src) {
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return script.src;
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} else if (script.id) {
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return script.id;
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} else {
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return script.innerHTML;
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}
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}
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function reloadScript(script) {
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try {
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if (isValid(script)) {
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injectScript(script);
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}
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} catch (error) {
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console.error(`Blazor Script Reload failed to load script: ${getKey(script)}`, error);
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}
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}
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function isValid(script) {
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if (script.innerHTML.includes('document.write(')) {
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console.log(`Blazor Script Reload does not support scripts using document.write(): ${script.innerHTML}`);
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return false;
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}
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return true;
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}
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function injectScript(script) {
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return new Promise((resolve, reject) => {
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var newScript = document.createElement('script');
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// replicate attributes and content
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for (let i = 0; i < script.attributes.length; i++) {
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if (script.attributes[i].name !== 'data-reload') {
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newScript.setAttribute(script.attributes[i].name, script.attributes[i].value);
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}
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}
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newScript.nonce = script.nonce; // must be referenced explicitly
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newScript.innerHTML = script.innerHTML;
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// dynamically injected scripts cannot be async or deferred
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newScript.async = false;
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newScript.defer = false;
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newScript.onload = () => resolve();
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newScript.onerror = (error) => reject(error);
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// inject script element in head to force execution in Blazor
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document.head.appendChild(newScript);
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// remove data-reload attribute
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script.removeAttribute('data-reload');
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});
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} |