use cosnt instead of let

lib/lazy/content-lazy-loader.js

@@ -30,7 +30,17 @@ this.lazyLoader = this.lazyLoader || (() => {
 
 	function process() {
 		return new Promise(resolve => {
-			let timeoutId, maxTimeoutId, idleTimeoutId, srcAttributeChanged;
+			let timeoutId, srcAttributeChanged;
+			const idleTimeoutId = timeout.set(() => {
+				if (!srcAttributeChanged) {
+					timeout.clear(timeoutId);
+					lazyLoadEnd(maxTimeoutId, idleTimeoutId, observer, resolve);
+				}
+			}, IDLE_LAZY_LOADING_TIMEOUT);
+			const maxTimeoutId = timeout.set(() => {
+				timeout.clear(timeoutId);
+				lazyLoadEnd(maxTimeoutId, idleTimeoutId, observer, resolve);
+			}, MAX_LAZY_LOADING_TIMEOUT);
 			const observer = new MutationObserver(mutations => {
 				if (mutations.find(mutation => mutation.type == "attributes")) {
 					srcAttributeChanged = true;
@@ -42,16 +52,6 @@ this.lazyLoader = this.lazyLoader || (() => {
 			scriptBeforeElement.src = browser.runtime.getURL("lib/lazy/web-lazy-loader-before.js");
 			document.body.appendChild(scriptBeforeElement);
 			scriptBeforeElement.onload = () => scriptBeforeElement.remove();
-			idleTimeoutId = timeout.set(() => {
-				if (!srcAttributeChanged) {
-					timeout.clear(timeoutId);
-					lazyLoadEnd(maxTimeoutId, idleTimeoutId, observer, resolve);
-				}
-			}, IDLE_LAZY_LOADING_TIMEOUT);
-			maxTimeoutId = timeout.set(() => {
-				timeout.clear(timeoutId);
-				lazyLoadEnd(maxTimeoutId, idleTimeoutId, observer, resolve);
-			}, MAX_LAZY_LOADING_TIMEOUT);
 		});
 	}