View Source Phoenix.LiveView.JS (Phoenix LiveView v0.20.0)
Provides commands for executing JavaScript utility operations on the client.
JS commands support a variety of utility operations for common client-side needs, such as adding or removing CSS classes, setting or removing tag attributes, showing or hiding content, and transitioning in and out with animations. While these operations can be accomplished via client-side hooks, JS commands are DOM-patch aware, so operations applied by the JS APIs will stick to elements across patches from the server.
In addition to purely client-side utilities, the JS commands include a
rich push API, for extending the default phx- binding pushes with
options to customize targets, loading states, and additional payload values.
Client Utility Commands
The following utilities are included:
add_class- Add classes to elements, with optional transitionsremove_class- Remove classes from elements, with optional transitionsset_attribute- Set an attribute on elementsremove_attribute- Remove an attribute from elementsshow- Show elements, with optional transitionshide- Hide elements, with optional transitionstoggle- Shows or hides elements based on visibility, with optional transitionstransition- Apply a temporary transition to elements for animationsdispatch- Dispatch a DOM event to elements
For example, the following modal component can be shown or hidden on the client without a trip to the server:
alias Phoenix.LiveView.JS
def hide_modal(js \\ %JS{}) do
js
|> JS.hide(transition: "fade-out", to: "#modal")
|> JS.hide(transition: "fade-out-scale", to: "#modal-content")
end
def modal(assigns) do
~H"""
<div id="modal" class="phx-modal" phx-remove={hide_modal()}>
<div
id="modal-content"
class="phx-modal-content"
phx-click-away={hide_modal()}
phx-window-keydown={hide_modal()}
phx-key="escape"
>
<button class="phx-modal-close" phx-click={hide_modal()}>✖</button>
<p><%= @text %></p>
</div>
</div>
"""
endEnhanced push events
The push/1 command allows you to extend the built-in pushed event handling
when a phx- event is pushed to the server. For example, you may wish to
target a specific component, specify additional payload values to include
with the event, apply loading states to external elements, etc. For example,
given this basic phx-click event:
<button phx-click="inc">+</button>Imagine you need to target your current component, and apply a loading state to the parent container while the client awaits the server acknowledgement:
alias Phoenix.LiveView.JS
<button phx-click={JS.push("inc", loading: ".thermo", target: @myself)}>+</button>Push commands also compose with all other utilities. For example, to add a class when pushing:
<button phx-click={
JS.push("inc", loading: ".thermo", target: @myself)
|> JS.add_class("warmer", to: ".thermo")
}>+</button>Any phx-value-* attributes will also be included in the payload, their
values will be overwritten by values given directly to push/1. Any
phx-target attribute will also be used, and overwritten.
<button
phx-click={JS.push("inc", value: %{limit: 40})}
phx-value-room="bedroom"
phx-value-limit="this value will be 40"
phx-target={@myself}
>+</button>
Custom JS events with JS.dispatch/1 and window.addEventListener
dispatch/1 can be used to dispatch custom JavaScript events to
elements. For example, you can use JS.dispatch("click", to: "#foo"),
to dispatch a click event to an element.
This also means you can augment your elements with custom events,
by using JavaScript's window.addEventListener and invoking them
with dispatch/1. For example, imagine you want to provide
a copy-to-clipboard functionality in your application. You can
add a custom event for it:
window.addEventListener("my_app:clipcopy", (event) => {
if ("clipboard" in navigator) {
const text = event.target.textContent;
navigator.clipboard.writeText(text);
} else {
alert("Sorry, your browser does not support clipboard copy.");
}
});Now you can have a button like this:
<button phx-click={JS.dispatch("my_app:clipcopy", to: "#element-with-text-to-copy")}>
Copy content
</button>The combination of dispatch/1 with window.addEventListener is
a powerful mechanism to increase the amount of actions you can trigger
client-side from your LiveView code.
You can also use window.addEventListener to listen to events pushed
from the server. You can learn more in our JS interoperability guide.
Summary
Functions
Adds classes to elements.
Dispatches an event to the DOM.
Executes JS commands located in element attributes.
See exec/1.
Sends focus to a selector.
See focus/1.
Sends focus to the first focusable child in selector.
Hides elements.
See hide/1.
Sends a navigation event to the server and updates the browser's pushState history.
Sends a patch event to the server and updates the browser's pushState history.
See patch/1.
Focuses the last pushed element.
Pushes an event to the server.
See push/1.
Pushes focus from the source element to be later popped.
Removes an attribute from elements.
Removes classes from elements.
Sets an attribute on elements.
Shows elements.
See show/1.
Toggles element visibility.
See toggle/1.
Transitions elements.
Types
@opaque t()
Functions
Adds classes to elements.
names- The string of classes to add.
Options
:to- The optional DOM selector to add classes to. Defaults to the interacted element.:transition- The string of classes to apply before adding classes or a 3-tuple containing the transition class, the class to apply to start the transition, and the ending transition class, such as:{"ease-out duration-300", "opacity-0", "opacity-100"}:time- The time to apply the transition from:transition. Defaults 200
Examples
<div id="item">My Item</div>
<button phx-click={JS.add_class("highlight underline", to: "#item")}>
highlight!
</button>See add_class/1.
See add_class/1.
Dispatches an event to the DOM.
event- The string event name to dispatch.
Note: All events dispatched are of a type
CustomEvent,
with the exception of "click". For a "click", a
MouseEvent
is dispatched to properly simulate a UI click.
For emitted CustomEvent's, the event detail will contain a dispatcher,
which references the DOM node that dispatched the JS event to the target
element.
Options
:to- The optional DOM selector to dispatch the event to. Defaults to the interacted element.:detail- The optional detail map to dispatch along with the client event. The details will be available in theevent.detailattribute for event listeners.:bubbles– The boolean flag to bubble the event or not. Defaulttrue.
Examples
window.addEventListener("click", e => console.log("clicked!", e.detail))
<button phx-click={JS.dispatch("click", to: ".nav")}>Click me!</button>See dispatch/2.
Executes JS commands located in element attributes.
attr- The string attribute where the JS command is specified
Options
:to- The optional DOM selector to fetch the attribute from. Defaults to the current element.
Examples
<div id="modal" phx-remove={JS.hide("#modal")}>...</div>
<button phx-click={JS.exec("phx-remove", to: "#modal")}>close</button>See exec/1.
See exec/1.
Sends focus to a selector.
Options
:to- The optional DOM selector to send focus to. Defaults to the current element.
Examples
JS.focus(to: "main")See focus/1.
Sends focus to the first focusable child in selector.
Options
:to- The optional DOM selector to focus. Defaults to the current element.
Examples
JS.focus_first(to: "#modal")See focus_first/1.
Hides elements.
Options
:to- The optional DOM selector to hide. Defaults to the interacted element.:transition- The string of classes to apply before hiding or a 3-tuple containing the transition class, the class to apply to start the transition, and the ending transition class, such as:{"ease-out duration-300", "opacity-100", "opacity-0"}:time- The time to apply the transition from:transition. Defaults 200
During the process, the following events will be dispatched to the hidden elements:
- When the action is triggered on the client,
phx:hide-startis dispatched. - After the time specified by
:time,phx:hide-endis dispatched.
Examples
<div id="item">My Item</div>
<button phx-click={JS.hide(to: "#item")}>
hide!
</button>
<button phx-click={JS.hide(to: "#item", transition: "fade-out-scale")}>
hide fancy!
</button>See hide/1.
Sends a patch event to the server and updates the browser's pushState history.
Options
:replace- Whether to replace the browser's pushState history. Defaults false.
Examples
JS.patch("/my-path")See patch/1.
See patch/1.
Focuses the last pushed element.
Examples
JS.pop_focus()Pushes an event to the server.
event- The string event name to push.
Options
:target- The selector or component ID to push to. This value will overwrite anyphx-targetattribute present on the element.:loading- The selector to apply the phx loading classes to.:page_loading- Boolean to trigger the phx:page-loading-start and phx:page-loading-stop events for this push. Defaults tofalse.:value- The map of values to send to the server. These values will be merged over anyphx-value-*attributes that are present on the element. All keys will be treated as strings when merging.
Examples
<button phx-click={JS.push("clicked")}>click me!</button>
<button phx-click={JS.push("clicked", value: %{id: @id})}>click me!</button>
<button phx-click={JS.push("clicked", page_loading: true)}>click me!</button>See push/1.
See push/1.
Pushes focus from the source element to be later popped.
Options
:to- The optional DOM selector to push focus to. Defaults to the current element.
Examples
JS.push_focus()
JS.push_focus(to: "#my-button")See push_focus/1.
Removes an attribute from elements.
attr- The string attribute name to remove.
Options
:to- The optional DOM selector to remove attributes from. Defaults to the interacted element.
Examples
<button phx-click={JS.remove_attribute("aria-expanded", to: "#dropdown")}>
hide
</button>See remove_attribute/1.
See remove_attribute/1.
Removes classes from elements.
names- The string of classes to remove.
Options
:to- The optional DOM selector to remove classes from. Defaults to the interacted element.:transition- The string of classes to apply before removing classes or a 3-tuple containing the transition class, the class to apply to start the transition, and the ending transition class, such as:{"ease-out duration-300", "opacity-0", "opacity-100"}:time- The time to apply the transition from:transition. Defaults 200
Examples
<div id="item">My Item</div>
<button phx-click={JS.remove_class("highlight underline", to: "#item")}>
remove highlight!
</button>See remove_class/1.
See remove_class/1.
Sets an attribute on elements.
Accepts a tuple containing the string attribute name/value pair.
Options
:to- The optional DOM selector to add attributes to. Defaults to the interacted element.
Examples
<button phx-click={JS.set_attribute({"aria-expanded", "true"}, to: "#dropdown")}>
show
</button>See set_attribute/1.
See set_attribute/1.
Shows elements.
Options
:to- The optional DOM selector to show. Defaults to the interacted element.:transition- The string of classes to apply before showing or a 3-tuple containing the transition class, the class to apply to start the transition, and the ending transition class, such as:{"ease-out duration-300", "opacity-0", "opacity-100"}:time- The time to apply the transition from:transition. Defaults 200:display- The optional display value to set when showing. Defaults"block".
During the process, the following events will be dispatched to the shown elements:
- When the action is triggered on the client,
phx:show-startis dispatched. - After the time specified by
:time,phx:show-endis dispatched.
Examples
<div id="item">My Item</div>
<button phx-click={JS.show(to: "#item")}>
show!
</button>
<button phx-click={JS.show(to: "#item", transition: "fade-in-scale")}>
show fancy!
</button>See show/1.
Toggles element visibility.
Options
:to- The optional DOM selector to toggle. Defaults to the interacted element.:in- The string of classes to apply when toggling in, or a 3-tuple containing the transition class, the class to apply to start the transition, and the ending transition class, such as:{"ease-out duration-300", "opacity-0", "opacity-100"}:out- The string of classes to apply when toggling out, or a 3-tuple containing the transition class, the class to apply to start the transition, and the ending transition class, such as:{"ease-out duration-300", "opacity-100", "opacity-0"}:time- The time to apply the transition:inand:outclasses. Defaults 200:display- The optional display value to set when toggling in. Defaults"block".
When the toggle is complete on the client, a phx:show-start or phx:hide-start, and
phx:show-end or phx:hide-end event will be dispatched to the toggled elements.
Examples
<div id="item">My Item</div>
<button phx-click={JS.toggle(to: "#item")}>
toggle item!
</button>
<button phx-click={JS.toggle(to: "#item", in: "fade-in-scale", out: "fade-out-scale")}>
toggle fancy!
</button>See toggle/1.
Transitions elements.
transition- The string of classes to apply before removing classes or a 3-tuple containing the transition class, the class to apply to start the transition, and the ending transition class, such as:{"ease-out duration-300", "opacity-0", "opacity-100"}
Transitions are useful for temporarily adding an animation class to element(s), such as for highlighting content changes.
Options
:to- The optional DOM selector to apply transitions to. Defaults to the interacted element.:time- The time to apply the transition from:transition. Defaults 200
Examples
<div id="item">My Item</div>
<button phx-click={JS.transition("shake", to: "#item")}>Shake!</button>See transition/1.
See transition/1.