Function recordHistory

dash/dash-renderer/src/reducers/reducer.js:115–146

(reducer)

}

function recordHistory(reducer) {
    return function (state, action) {
        // Record initial state
        const {type, payload} = action;
        if (type === 'ON_PROP_CHANGE') {
            // history records all prop changes that are inputs.
            const historyEntry = getInputHistoryState(payload, state, true);
            if (historyEntry && !isEmpty(historyEntry.props)) {
                state.history.present = historyEntry;
            }
        }

        const nextState = reducer(state, action);

        if (type === 'ON_PROP_CHANGE' && payload.source !== 'response') {
            /*
             * if the prop change is an input, then
             * record it so that it can be played back
             */
            const historyEntry = getInputHistoryState(payload, nextState);
            if (historyEntry && !isEmpty(historyEntry.props)) {
                nextState.history = {
                    past: [...nextState.history.past, state.history.present],
                    present: historyEntry,
                    future: []
                };
            }
        }

        return nextState;
    };
}

function reloaderReducer(reducer) {
    return function (state, action) {