User:Ilmari Karonen/unwatchredlinks.js

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Documentation for this user script can be added at User:Ilmari Karonen/unwatchredlinks.

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/*
This script adds a "Select all nonexistent pages" button to the watchlist edit page
([[Special:Watchlist/edit]]).  To install it, add the line:
  importScript('User:Ilmari_Karonen/unwatchredlinks.js');
to your monobook.js page (or to the corresponding page for other skins).

The button will only select pages that do not exist and do not have existing talk
pages either.  As an unintended -- but probably desirable -- side effect, it will
not select user pages of any existing users either.
*/

if (mw.config.get('wgCanonicalNamespace') == "Special" && mw.config.get('wgCanonicalSpecialPageName') == "Watchlist") {
    addOnloadHook(function () {
        // It's somewhat hard to tell if we're on the "edit watchlist" subpage,
        // so we'll just proceed as if we were and abort if something looks odd.
        var form = document.getElementsByTagName("form")[0];
        if (!form) return;
        // This is our main check for which page we're on:
        if (!/[&?]action=edit(&|$)/.test(form.action)) return;
        var inputs = form.getElementsByTagName("input");
        if (!inputs || inputs.length < 1) return;
        var submit = inputs[inputs.length - 1];
        if (submit.type != "submit") return;
        inputs = null;

        // Okay so far, now add the custom button.
        var button = document.createElement("input");
        button.type = "button";
        button.value = "Select all nonexistent pages";
        button.onclick = function () {
            // Here's the code for what happens when you click it. 

            var items = form.getElementsByTagName("li");
            if (!items || items.length < 1) return;
            for (var i = 0; i < items.length; i++) {
                var input = items[i].getElementsByTagName("input")[0];
                if (!input || input.getAttribute("type") != "checkbox") continue;
                var isRedlink = true;  // assume redlink until proven otherwise
                var links = items[i].getElementsByTagName("a");
                for (var j = 0; isRedlink && j < links.length; j++) {
                    isRedlink = /[&?]action=edit(&|$)/.test(links[j].href);
                }
                input.checked = isRedlink;
            }
        };

        // Now add the button to the page.
        if (submit.nextSibling)
            submit.parentNode.insertBefore(button, submit.nextSibling);
        else
            submit.parentNode.appendChild(button);
        // Looks nicer with a space...
        button.parentNode.insertBefore(document.createTextNode(" "), button);
    });
}