A custom function is a software code that can be used to automate a process and this allows you to automate a notification, call a webhook, or perform logic immediately after a workflow rule is triggered. This feature helps to automate complex tasks and calculations. 

projectsV3Endpoint = "https://projectsapi.zoho.com/api/v3/portal/";

endPoint = "https://projectsapi.zoho.com/restapi/portal/";

nextTaskName = "hello"; // update the next task name here and make sure its unique

params = Map();

params.put("filter",{"criteria":{{"field_name":"name","criteria_condition":"is","value":{nextTaskName}}},"pattern":"1"});

getTasks = invokeurl

[

url :projectsV3Endpoint + portalId + "/projects/" + projectId + "/tasks"

type :GET

parameters:params

connection:"connectionprojects"

];

nextTaskId = getTasks.get("tasks").get(0).get("id");

updateTaskParam = Map();

updateTaskParam.put("start_date",toString(customDate,"MM-dd-yyyy"));

updateTaskParam.put("end_date",toString(customDate,"MM-dd-yyyy"));

updateTaskResponse = zoho.projects.update(portalId,projectId,"Tasks",nextTaskId,updateTaskParam,"connectionprojects");

return "success";