Method clientside_callback

dash/dash.py:1414–1487

Create a callback that updates the output by calling a clientside (JavaScript) function instead of a Python function. Unlike `@app.callback`, `clientside_callback` is not a decorator: it takes either a `dash.dependencies.ClientsideFunction(namespace, function_name)`

(self, clientside_function, *args, **kwargs)

        )

    def clientside_callback(self, clientside_function, *args, **kwargs):
        """Create a callback that updates the output by calling a clientside
        (JavaScript) function instead of a Python function.

        Unlike `@app.callback`, `clientside_callback` is not a decorator:
        it takes either a
        `dash.dependencies.ClientsideFunction(namespace, function_name)`
        argument that describes which JavaScript function to call
        (Dash will look for the JavaScript function at
        `window.dash_clientside[namespace][function_name]`), or it may take
        a string argument that contains the clientside function source.

        For example, when using a `dash.dependencies.ClientsideFunction`:
        ```
        app.clientside_callback(
            ClientsideFunction('my_clientside_library', 'my_function'),
            Output('my-div' 'children'),
            [Input('my-input', 'value'),
             Input('another-input', 'value')]
        )
        ```

        With this signature, Dash's front-end will call
        `window.dash_clientside.my_clientside_library.my_function` with the
        current values of the `value` properties of the components `my-input`
        and `another-input` whenever those values change.

        Include a JavaScript file by including it your `assets/` folder. The
        file can be named anything but you'll need to assign the function's
        namespace to the `window.dash_clientside` namespace. For example,
        this file might look:
        ```
        window.dash_clientside = window.dash_clientside || {};
        window.dash_clientside.my_clientside_library = {
            my_function: function(input_value_1, input_value_2) {
                return (
                    parseFloat(input_value_1, 10) +
                    parseFloat(input_value_2, 10)
                );
            }
        }
        ```

        Alternatively, you can pass the JavaScript source directly to
        `clientside_callback`. In this case, the same example would look like:
        ```
        app.clientside_callback(
            '''
            function(input_value_1, input_value_2) {
                return (
                    parseFloat(input_value_1, 10) +
                    parseFloat(input_value_2, 10)
                );
            }
            ''',
            Output('my-div' 'children'),
            [Input('my-input', 'value'),
             Input('another-input', 'value')]