clearDownloadsButton.uc.js

// ==UserScript==
// @name           Clear Downloads Panel Button
// @version        1.3.1
// @author         aminomancer
// @homepage       https://github.com/aminomancer/uc.css.js
// @description    Place a "Clear Downloads" button in the downloads panel, right next to the "Show all downloads" button.
// ==/UserScript==

(function () {
    const config = {
        "Label in sentence case": true, // the "Show all downloads" button is in sentence case, but the localized "Clear Downloads" button string is from a context menu, so it's in "Title Case". if you want both in sentence case use this. I've tried to account for other alphabets or RTL languages but user will be the judge
    };
    class ClearDLPanel {
        constructor() {
            this.makeButton();
            this.setCountHandler();
            Services.obs.addObserver(this, "downloads-panel-count-changed");
        }
        async genStrings() {
            this.strings = await new Localization(["browser/downloads.ftl"], true);
            const messages = await this.strings.formatMessages(["downloads-cmd-clear-downloads"]);
            this.label = messages[0].attributes[0].value;
            this.accessKey = messages[0].attributes[1].value;
            return [this.label, this.accessKey];
        }
        async makeButton() {
            this.clearPanelButton = document.createXULElement("button");
            let strings = await this.genStrings();
            let labelString = config["Label in sentence case"]
                ? this.sentenceCase(strings[0])
                : strings[0];
            for (const [key, val] of Object.entries({
                id: "clearDownloadsPanel",
                class:
                    DownloadsView.downloadsHistory.className ||
                    "downloadsPanelFooterButton subviewbutton panel-subview-footer-button toolbarbutton-1",
                command: `downloadsCmd_clearList`,
                onclick: `DownloadsPanel.hidePanel();`,
                label: labelString,
                accesskey: strings[1],
                flex: "1",
                pack: "start",
            }))
                this.clearPanelButton.setAttribute(key, val);
            DownloadsView.downloadsHistory.after(this.clearPanelButton);
            this.clearPanelButton.hidden = !DownloadsView._visibleViewItems?.size > 0;
        }
        sentenceCase(str) {
            return str
                .toLocaleLowerCase()
                .replace(RTL_UI ? /.$/i : /^./i, function (letter) {
                    return letter.toLocaleUpperCase();
                })
                .trim();
        }
        setCountHandler() {
            eval(
                `DownloadsView._itemCountChanged = function ${DownloadsView._itemCountChanged
                    .toSource()
                    .replace(
                        /hiddenCount \> 0\;\n/,
                        `hiddenCount > 0;\n    Services.obs.notifyObservers(null, "downloads-panel-count-changed", String(count));\n`
                    )}`
            );
        }
        observe(_sub, _top, data) {
            this.clearPanelButton.hidden = parseInt(data) < 1;
        }
    }

    function init() {
        new ClearDLPanel();
    }

    if (gBrowserInit.delayedStartupFinished) init();
    else {
        let delayedListener = (subject, topic) => {
            if (topic == "browser-delayed-startup-finished" && subject == window) {
                Services.obs.removeObserver(delayedListener, topic);
                init();
            }
        };
        Services.obs.addObserver(delayedListener, "browser-delayed-startup-finished");
    }
})();