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(async() => {
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    function set(key, value) {
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        chrome.storage.local.set({ [key]: value })
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    };
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    function get(key) {
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        return new Promise(resolve => {
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            chrome.storage.local.get([key], result => {
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                resolve(result[key])
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            })
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        })
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    };
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    function validURL(str) {
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        var pattern = new RegExp('^(https?:\\/\\/)?'+ // protocol
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            '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|'+ // domain name
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            '((\\d{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address
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            '(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*'+ // port and path
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            '(\\?[;&a-z\\d%_.~+=-]*)?'+ // query string
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            '(\\#[-a-z\\d_]*)?$','i'); // fragment locator
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        return !!pattern.test(str) || new URL(str).hostname === "localhost";
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    }
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    const checkbox = document.querySelector(".check")
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    const input = document.querySelector("input")
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    input.value = await get("url") || "";
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    checkbox.checked = await get("checked") || false;
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    input.onchange = () => {
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        document.querySelector("p").innerHTML = ""
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    }
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    checkbox.addEventListener("click", async (event) => {
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        if (await get("checked")) {
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            // if already checked, no need to run checks
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            // set checked to new value, which should be false
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            set("checked", checkbox.checked);
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        } else {
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            // if we're turning on checked, we need to run a few checks
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            if (validURL(input.value)) {
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                // if the URL is valid, update url and checked to their latest values.
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                set("url", input.value);
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                set("checked", checkbox.checked);
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            } else {
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                // if the URL is invalid, scream at them until they burst into tears
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                document.querySelector("p").innerHTML = "Invalid URL";
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                checkbox.checked = false;
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            }
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        }
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    })
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})();
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