File for save contexts DialogFlow when use Default Intent

dfQuery.ts

export type DfRequest = {
  headers: object;
  body: {
    session: string;
    responseId: string;
    queryResult: IQueryResult;
    originalDetectIntentRequest: IOriginalDetectIntentRequest;
  };
};

export type IQueryParameters = {
  age?: number;
};

export type IQueryResult = {
  queryText: string;
  parameters: IQueryParameters;
  allRequiredParamsPresent: boolean;
  fulfillmentText: object;
  fulfillmentMessages: [
    {
      text: {
        text: Array<string>;
      };
    }
  ];
  outputContexts: OutputContexts;
  intent: {
    name: string;
    displayName: string;
  };
  intentDetectionConfidence: 1;
  diagnosticInfo: {};
  languageCode: string;
};

export interface IOriginalDetectIntentRequest {
  payload: {
    data: {
      date: number;
      message_id: number;
      text: string;
      from: {
        id: number;
        language_code: string;
        first_name: string;
        username: string;
      };
      chat: { id: string; type: string };
    };
  };
}

export type OutputContexts = Array<ItemContext>;

export type ItemContext = {
  name: string;
  parameters: ITargetContextParams;
};
          
export interface ITargetContextParams {
//here you write your params field
}

saveDefaultContexts.ts

import { WebhookClient } from "dialogflow-fulfillment";
import { IQueryResult, ITargetContextParams } from "dfQuery";

type IReqContext = {
  name: string;
  parameters: object;
  lifespan: number;
};

export async function saveDefaultContexts(
  agent: WebhookClient,
  queryResult: IQueryResult
) {
  console.log(
    "<--------------------------saveDefaultContexts running-------------------------->"
  );
  try {
    const targetContext = agent.context.get("YOUR-MAIN-CONTEXT-WITH-ALL-PARAMS");

    const targetContextParams: ITargetContextParams = targetContext
      ? JSON.parse(JSON.stringify(targetContext.parameters))
      : {};

    const contexts = queryResult.outputContexts.map((item) => {
      const tmp = item.name.split("/").slice();
      return tmp[tmp.length - 1];
    });

    contexts.forEach((context) => {
      const reqContext: IReqContext =
        context === "YOUR-MAIN-CONTEXT-WITH-ALL-PARAMS"
          ? {
              name: context,
              parameters: targetContextParams,
              lifespan: 1,
            }
          : {
              name: context,
              parameters: {},
              lifespan: 1,
            };
      try {
        agent.context.set(reqContext);
      } catch (e) {
        console.log("ERROR: ", e);
      }
    });

    agent.end("");
  } catch (e) {
    console.log(e);
    throw new Error("Error in `saveDefaultContext`");
  }
}