修改了下

selectAll.change(function (e) {
    if (e.target.checked) {
        deselectAllLabel.prev().hide();
        deselectAllLabel.show();
        langs.map(function () {
            this.checked = true;
        });
    } else {
        deselectAllLabel.prev().show();
        deselectAllLabel.hide();
        langs.map(function () {
            this.checked = false;
        });
    }
});

invertSelect.click(function () {
    langs.map(function () {
        if (this.checked) {
            this.checked = false;
        } else {
            this.checked = true;
        }
        $(this).change();
    });
});

langs.map(function () {
    $(this).change(function () {
        var count_select = 0;
        var count_deselect = 0;
        for (let i = 0; i < langs.length; i++) {
            if (langs[i].checked) {
                count_select ++;
            } else {
                count_deselect ++;
            }
        }
        if (count_select === langs.length) {
            selectAll[0].checked = true;
            selectAll.change();
        }
        if (count_deselect !== 0) {
            selectAll[0].checked = false;
            deselectAllLabel.prev().show();
            deselectAllLabel.hide();
        }
    });
});