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pret

component [source]

Decorator to turn a Python function into a Pret component, that will be rendered by React.

Parameters

PARAMETER DESCRIPTION
fn

TYPE: Callable

use_callback [source]

Returns a memoized callback function. The callback will be stable across re-renders, as long as the dependencies don't change, meaning the last callback function passed to this function will be used between two re-renders.

Note

Ensure that dependencies are simple values like int, str, bool to avoid unnecessary re-executions, as these values are converted to javascript objects, and converting complex objects may not ensure referential equality.

Parameters

PARAMETER DESCRIPTION
callback

The callback function

TYPE: CallbackType

dependencies

The dependencies that will trigger a re-execution of the callback.

TYPE: Optional[List] DEFAULT: None

use_effect [source]

The useEffect hook allows you to perform side effects in function components. Side effects can include data fetching, subscriptions, manually changing the DOM, and more.

The effect runs after every render by default. If dependencies are provided, the effect runs whenever those values change. Therefore, if dependencies is an empty array, the effect runs only once after the initial render.

Note

Ensure that dependencies are simple values like int, str, bool to avoid unnecessary re-executions, as these values are converted to javascript objects, and converting complex objects may not ensure referential equality.

Parameters

PARAMETER DESCRIPTION
effect

A function containing the side effect logic. It can optionally return a cleanup function.

TYPE: Callable

dependencies

An optional array of dependencies that determines when the effect runs.

TYPE: Optional[List] DEFAULT: None

use_memo [source]

Returns a memoized value, computed from the provided function. The function will only be re-executed if any of the dependencies change.

Note

Ensure that dependencies are simple values like int, str, bool to avoid unnecessary re-executions, as these values are converted to javascript objects, and converting complex objects may not ensure referential equality.

Parameters

PARAMETER DESCRIPTION
fn

The function to run to compute the memoized value

TYPE: Callable[[], FunctionReturnType]

dependencies

The dependencies that will trigger a re-execution of the function

TYPE: List

RETURNS DESCRIPTION
FunctionReturnType

The value

use_ref [source]

Returns a mutable ref object whose .current property is initialized to the passed argument.

The returned object will persist for the full lifetime of the component.

Parameters

PARAMETER DESCRIPTION
initial_value

The initial value of the ref

TYPE: RefValueType

RETURNS DESCRIPTION
RefType[RefValueType]

The ref object

use_state [source]

Returns a stateful value, and a function to update it.

Examples

from pret.ui.react import div, button, p
from pret import component, use_state


@component
def CounterApp():
    count, set_count = use_state(0)

    def increment():
        set_count(count + 1)

    return div(p(count), button({"onClick": increment}, "Increment"))

Parameters

PARAMETER DESCRIPTION
initial_value

The initial value of the state

TYPE: StateValueType

RETURNS DESCRIPTION
Tuple[StateValueType, Callable[[StateValueType], None]]
  • The current value of the state
  • A function to update the state

use_tracked [source]

This hook is used to track the access made on a proxy object. You can also use the returned object to change the proxy object.

Parameters

PARAMETER DESCRIPTION
proxy_object

A proxy object, like the one returned by proxy({...})

RETURNS DESCRIPTION
TrackedProxyType

A tracked proxy object

use_event_callback [source]

This hook is used to store a callback function that will be called when an event is triggered. The callback function can be changed without triggering a re-render of the component. The function returns a wrapped callback function that will in turn call the stored callback function.

Warning

Do not use this hook if the rendering of the component depends on the callback function.

Parameters

PARAMETER DESCRIPTION
callback

The callback function

TYPE: CallbackType

RETURNS DESCRIPTION
CallbackType

The wrapped callback function