Function handle_grouped_callback_args

dash/dependencies.py:332–363

Split args into outputs, inputs and states

(args, kwargs)

def handle_grouped_callback_args(args, kwargs):
    """Split args into outputs, inputs and states"""
    prevent_initial_call = kwargs.get("prevent_initial_call", None)
    if prevent_initial_call is None and args and isinstance(args[-1], bool):
        args, prevent_initial_call = args[:-1], args[-1]

    # flatten args, to support the older syntax where outputs, inputs, and states
    # each needed to be in their own list
    flat_args = []
    for arg in args:
        flat_args += arg if isinstance(arg, (list, tuple)) else [arg]

    outputs = extract_grouped_output_callback_args(flat_args, kwargs)
    flat_outputs = flatten_grouping(outputs)

    if isinstance(outputs, (list, tuple)) and len(outputs) == 1:
        out0 = kwargs.get("output", args[0] if args else None)
        if not isinstance(out0, (list, tuple)):
            # unless it was explicitly provided as a list, a single output
            # should be unwrapped. That ensures the return value of the
            # callback is also not expected to be wrapped in a list.
            outputs = outputs[0]

    inputs_state = extract_grouped_input_state_callback_args(flat_args, kwargs)
    flat_inputs, flat_state, input_state_indices = compute_input_state_grouping_indices(
        inputs_state
    )

    types = Input, Output, State
    validate_callback(flat_outputs, flat_inputs, flat_state, flat_args, types)

    return outputs, flat_inputs, flat_state, input_state_indices, prevent_initial_call


def extract_callback_args(args, kwargs, name, type_):