Implement dynamic navs (i.e., nav_insert(), nav_remove(), nav_show(),…

… nav_hide())

docs/source/index.rst

@@ -136,6 +136,10 @@ Create segments of UI content.
     ui.navset_pill
     ui.navset_pill_card
     ui.navset_pill_list
+    ui.nav_insert
+    ui.nav_remove
+    ui.nav_show
+    ui.nav_hide
 
 
 UI panels

shiny/_modules.py

@@ -1,6 +1,6 @@
 __all__ = ("Module",)
 
-from typing import Any, Callable, Optional
+from typing import Any, Callable, Optional, Dict
 
 from htmltools import TagChildArg
 
@@ -117,6 +117,15 @@ def __init__(self, ns: str, parent_session: Session) -> None:
     def __getattr__(self, attr: str) -> Any:
         return getattr(self._parent, attr)
 
+    def send_input_message(self, id: str, message: Dict[str, object]) -> None:
+        return super().send_input_message(self.ns(id), message)
+
+    def ns(self, id: Optional[str] = None) -> str:
+        if id is None:
+            return self._ns
+        else:
+            return self._ns + "-" + id
+
 
 @add_example()
 class Module:

shiny/examples/nav_insert/app.py

@@ -0,0 +1,57 @@
+from shiny import *
+
+app_ui = ui.page_fluid(
+    ui.layout_sidebar(
+        ui.panel_sidebar(
+            ui.input_action_button("add", "Add 'Dynamic' tab"),
+            ui.input_action_button("removeFoo", "Remove 'Foo' tabs"),
+            ui.input_action_button("addFoo", "Add New 'Foo' tab"),
+        ),
+        ui.panel_main(
+            ui.navset_tab(
+                ui.nav("Hello", "This is the hello tab"),
+                ui.nav("Foo", "This is the Foo tab", value="Foo"),
+                ui.nav_menu(
+                    "Static",
+                    ui.nav("Static 1", "Static 1", value="s1"),
+                    ui.nav("Static 2", "Static 2", value="s2"),
+                    value="Menu",
+                ),
+                id="tabs",
+            ),
+        ),
+    )
+)
+
+
+def server(input: Inputs, output: Outputs, session: Session):
+    @reactive.Effect()
+    @event(input.add)
+    def _():
+        id = "Dynamic-" + str(input.add())
+        ui.nav_insert(
+            "tabs",
+            ui.nav(id, id),
+            target="s2",
+            position="before",
+        )
+
+    @reactive.Effect()
+    @event(input.removeFoo)
+    def _():
+        ui.nav_remove("tabs", target="Foo")
+
+    @reactive.Effect()
+    @event(input.addFoo)
+    def _():
+        n = str(input.addFoo())
+        ui.nav_insert(
+            "tabs",
+            ui.nav("Foo-" + n, "This is the new Foo-" + n + " tab", value="Foo"),
+            target="Menu",
+            position="before",
+            select=True,
+        )
+
+
+app = App(app_ui, server)

shiny/examples/nav_show/app.py

@@ -0,0 +1,48 @@
+from shiny import *
+
+app_ui = ui.page_navbar(
+    ui.nav(
+        "Home",
+        ui.input_action_button("hideTab", "Hide 'Foo' tab"),
+        ui.input_action_button("showTab", "Show 'Foo' tab"),
+        ui.input_action_button("hideMenu", "Hide 'More' nav_menu"),
+        ui.input_action_button("showMenu", "Show 'More' nav_menu"),
+    ),
+    ui.nav("Foo", "This is the foo tab"),
+    ui.nav("Bar", "This is the bar tab"),
+    ui.nav_menu(
+        "More",
+        ui.nav("Table", "Table page"),
+        ui.nav("About", "About page"),
+        "------",
+        "Even more!",
+        ui.nav("Email", "Email page"),
+    ),
+    title="Navbar page",
+    id="tabs",
+)
+
+
+def server(input: Inputs, output: Outputs, session: Session):
+    @reactive.Effect()
+    @event(input.hideTab)
+    def _():
+        ui.nav_hide("tabs", target="Foo")
+
+    @reactive.Effect()
+    @event(input.showTab)
+    def _():
+        ui.nav_show("tabs", target="Foo")
+
+    @reactive.Effect()
+    @event(input.hideMenu)
+    def _():
+        ui.nav_hide("tabs", target="More")
+
+    @reactive.Effect()
+    @event(input.showMenu)
+    def _():
+        ui.nav_show("tabs", target="More")
+
+
+app = App(app_ui, server)

shiny/session/_session.py

@@ -670,6 +670,9 @@ def _process_ui(self, ui: TagChildArg) -> RenderedDeps:
 
         return {"deps": deps, "html": res["html"]}
 
+    def ns(self, id: Optional[str] = None) -> Optional[str]:
+        return id
+
 
 # ======================================================================================
 # Inputs

shiny/ui/__init__.py

@@ -20,6 +20,7 @@
 from ._markdown import *
 from ._modal import *
 from ._navs import *
+from ._navs_dynamic import *
 from ._notification import *
 from ._output import *
 from ._page import *

shiny/ui/_navs_dynamic.py

@@ -0,0 +1,197 @@
+__all__ = (
+    "nav_insert",
+    "nav_remove",
+    "nav_hide",
+    "nav_show",
+)
+
+import sys
+from typing import Optional, Union
+
+if sys.version_info >= (3, 8):
+    from typing import Literal
+else:
+    from typing_extensions import Literal
+
+from .._docstring import add_example
+from ._input_update import update_navs
+from ._navs import menu_string_as_nav
+from ..types import NavSetArg
+from ..session import Session, require_active_session
+from .._utils import run_coro_sync
+
+
+@add_example()
+def nav_insert(
+    id: str,
+    nav: Union[NavSetArg, str],
+    target: Optional[str] = None,
+    position: Literal["after", "before"] = "after",
+    select: bool = False,
+    session: Optional[Session] = None,
+) -> None:
+    """
+    Insert a new nav item into a navigation container.
+
+    Parameters
+    ----------
+    id
+        The ``id`` of the relevant navigation container (i.e., ``navset_*()`` object).
+    nav
+        The navigation item to insert (typically a :func:`~shiny.ui.nav` or
+        :func:`~shiny.ui.nav_menu`). A :func:`~shiny.ui.nav_menu` isn't allowed when the
+        ``target`` references an :func:`~shiny.ui.nav_menu` (or an item within it). A
+        string is only allowed when the ``target`` references a
+        :func:`~shiny.ui.nav_menu`.
+    target
+        The ``value`` of an existing :func:`shiny.ui.nav` item, next to which tab will
+        be added.
+    position
+        The position of the new nav item relative to the target nav item.
+    select
+        Whether the nav item should be selected upon insertion.
+    session
+        A :class:`~shiny.Session` instance. If not provided, it is inferred via
+        :func:`~shiny.session.get_current_session`.
+
+    See Also
+    --------
+    ~nav_remove
+    ~nav_show
+    ~nav_hide
+    ~shiny.ui.nav
+    """
+
+    session = require_active_session(session)
+
+    # N.B. this is only sensible if the target is a menu, but we don't know that,
+    # which could cause confusion of we decide to support top-level strings at some
+    # in the future.
+    if isinstance(nav, str):
+        nav = menu_string_as_nav(nav)
+
+    # N.B. shiny.js' is smart enough to know how to add active classes and href/id attrs
+    li_tag, div_tag = nav.resolve(selected=None)
+
+    msg = {
+        "inputId": session.ns(id),
+        "liTag": session._process_ui(li_tag),
+        "divTag": session._process_ui(div_tag),
+        "menuName": None,
+        "target": target,
+        "position": position,
+        "select": select,
+    }
+
+    def callback() -> None:
+        run_coro_sync(session._send_message({"shiny-insert-tab": msg}))
+
+    session.on_flush(callback, once=True)
+
+
+def nav_remove(id: str, target: str, session: Optional[Session] = None) -> None:
+    """
+    Remove a nav item from a navigation container.
+
+    Parameters
+    ----------
+    id
+        The ``id`` of the relevant navigation container (i.e., ``navset_*()`` object).
+    target
+        The ``value`` of an existing :func:`shiny.ui.nav` item to remove.
+    session
+        A :class:`~shiny.Session` instance. If not provided, it is inferred via
+        :func:`~shiny.session.get_current_session`.
+
+    See Also
+    --------
+    ~nav_insert
+    ~nav_show
+    ~nav_hide
+    ~shiny.ui.nav
+    """
+
+    session = require_active_session(session)
+
+    msg = {"inputId": session.ns(id), "target": target}
+
+    def callback() -> None:
+        run_coro_sync(session._send_message({"shiny-remove-tab": msg}))
+
+    session.on_flush(callback, once=True)
+
+
+def nav_show(
+    id: str, target: str, select: bool = False, session: Optional[Session] = None
+) -> None:
+    """
+    Show a navigation item
+
+    Parameters
+    ----------
+    id
+        The ``id`` of the relevant navigation container (i.e., ``navset_*()`` object).
+    target
+        The ``value`` of an existing :func:`shiny.ui.nav` item to show.
+    select
+        Whether the nav item's content should also be shown.
+    session
+        A :class:`~shiny.Session` instance. If not provided, it is inferred via
+        :func:`~shiny.session.get_current_session`.
+
+    Note
+    ----
+    For ``nav_show()`` to be relevant/useful, a :func:`shiny.ui.nav` item must
+    have been hidden using :func:`~nav_hide`.
+
+    See Also
+    --------
+    ~nav_hide
+    ~nav_insert
+    ~nav_remove
+    ~shiny.ui.nav
+    """
+
+    session = require_active_session(session)
+
+    if select:
+        update_navs(id, selected=target)
+
+    msg = {"inputId": session.ns(id), "target": target, "type": "show"}
+
+    def callback() -> None:
+        run_coro_sync(session._send_message({"shiny-change-tab-visibility": msg}))
+
+    session.on_flush(callback, once=True)
+
+
+def nav_hide(id: str, target: str, session: Optional[Session] = None) -> None:
+    """
+    Hide a navigation item
+
+    Parameters
+    ----------
+    id
+        The ``id`` of the relevant navigation container (i.e., ``navset_*()`` object).
+    target
+        The ``value`` of an existing :func:`shiny.ui.nav` item to hide.
+    session
+        A :class:`~shiny.Session` instance. If not provided, it is inferred via
+        :func:`~shiny.session.get_current_session`.
+
+    See Also
+    --------
+    ~nav_show
+    ~nav_insert
+    ~nav_remove
+    ~shiny.ui.nav
+    """
+
+    session = require_active_session(session)
+
+    msg = {"inputId": session.ns(id), "target": target, "type": "hide"}
+
+    def callback() -> None:
+        run_coro_sync(session._send_message({"shiny-change-tab-visibility": msg}))
+
+    session.on_flush(callback, once=True)