Callback example in Dash

callback.py

#### THIS IS A SUMMARY, THIS FILE WILL NOT RUN AS-IS ####

#### INPUTS to build_telemetry_chart ####
#https://github.com/omnisci/F1-demo/blob/726c56ba4e8c878abeef81b7cf680bd4d36a4bd2/f1dash/controls.py#L9-L32
#### reference lap: build list dynamically with callback
reflapmenu = dcc.Dropdown(
    id='reflapmenu',
    searchable=False,
    clearable=False,
    style=dict(minWidth = '250px', paddingRight = '15px', borderRadius = 0)
)

#### telemetry metrics: these are the reasonable values from the table
metricmenu = dcc.Dropdown(
    id='metricmenu',
    options=[
        {'label': 'speed', 'value': 'speed'},
        {'label': 'enginerpm', 'value': 'enginerpm'},
        {'label': 'brake', 'value': 'brake'},
        {'label': 'gear', 'value': 'gear'},
        {'label': 'steer', 'value': 'steer'},
        {'label': 'throttle', 'value': 'throttle'}
    ],
    value="speed",
    searchable=False,
    clearable=False,
    style=dict(minWidth = '250px', paddingRight = '15px', borderRadius = 0, color="#FFFFFF")
)

#### Listens for the 'value' field of 'reflapmenu' and 'value' field of 'metricmenu' to change
#### Runs build_telemetry_chart function, which sends its output to 'telemetry-graph' id
#https://github.com/omnisci/F1-demo/blob/726c56ba4e8c878abeef81b7cf680bd4d36a4bd2/f1dash/app.py#L182-L185
#callback decorator
@app.callback(Output('telemetry-graph', 'figure'),
              [Input('track-interval', 'n_intervals'), Input('reflapmenu', 'value'), Input('metricmenu', 'value')])
def build_telemetry_chart(notused, reflapvalue, metric):
...  


#### This code has 'telemetry-graph' as its id, so the results of build_telemetry_chart modifies the 'figure' field of 'telgraph'
#https://github.com/omnisci/F1-demo/blob/726c56ba4e8c878abeef81b7cf680bd4d36a4bd2/f1dash/telemetry.py#L31-L35
telgraph = dcc.Graph(id='telemetry-graph',
                    config={
                        'displayModeBar': True
                    }
                )