tasks.js

Tasks: Definition of tasks shown to app users

task

Task generation is configured in the tasks.js file. This file is a JavaScript module which defines an array of objects conforming to the Task schema detailed below. When defining tasks, all the data about contacts on the device (both people and places) along with all their reports are available. Tasks are available only for users of type “restricted to their place”. Tasks can pull in fields from reports and pass data as inputs to the form that opens when the task is selected, enabling richer user experiences.

Task generation occurs on the client periodically and creates documents which track the status of the task over time. To avoid performance issues the developer needs to be conscious about generating too many tasks. For example, to remind a user to do something every day, you could generate one task for each day and fill up the user’s device. The recommended approach is to only generate the tasks for the near future, or only once the previous task is resolved. To limit the impact of this misconfiguration, the CHT will only generate tasks that can be completed between 60 days in the past, and (as of 4.0.0) 180 days in the future.

See Also: Tasks Overview

tasks.js

propertytypedescriptionrequired
namestringA unique identifier for the task. Used for querying task completeness.yes, unique
iconstringThe icon to show alongside the task. Should correspond with a value defined in resources.json.no
titletranslation keyThe title of the task (labeled above).yes
appliesTo'contacts' or 'reports'Do you want to emit one task per report, or one task per contact? See Understanding the Parameters in the Task Schema.yes
appliesIffunction(contact, report)If appliesTo: 'contacts', this function is invoked once per contact and report is undefined. If appliesTo: 'reports', this function is invoked once per report. Return true if the task should appear for the given documents. See Understanding the Parameters in the Task Schema.no
appliesToTypestring[]Filters the contacts or reports for which appliesIf will be evaluated. If appliesTo: 'reports', this is an array of form codes. If appliesTo: 'contacts', this is an array of contact types. For example, ['person'] or ['clinic', 'health_center']. For example, ['pregnancy'] or ['P', 'pregnancy']. See Understanding the Parameters in the Task Schema.no
contactLabelstring or function(contact, report)Controls the label describing the subject of the task. Defaults to the name of the contact (contact.contact.name).no
resolvedIffunction(contact, report, event, dueDate)Return true to mark the task as “resolved”. A resolved task uses memory on the phone, but is not displayed.no, if any actions[n].type is 'report'
eventsobject[]An event is used to specify the timing of the task.yes
events[n].idstringA descriptive identifier. Used for querying task completeness.yes if task has multiple events, unique
events[n].daysintegerNumber of days after the doc’s reported_date that the event is dueyes, if dueDate is not set
events[n].dueDatefunction(event, contact, report)Returns a Date object for the day when this event is due.yes, if days is not set
events[n].startintegerNumber of days to show the task before it is due.yes
events[n].endintegerNumber of days to show the task after it is due.yes
actionsobject[]The actions (forms) that a user can access after clicking on a task. If you put multiple forms here, the user will see a task summary screen where they can select which action they would like to complete.yes
actions[n].type'report' or 'contact'When 'report', the action opens the given form. When 'contact', the action redirects to a contact’s profile page. Defaults to ‘report’.no
actions[n].formstringThe code of the form that should open when you select the action.yes, if actions[n].type is 'report'
actions[n].labeltranslation keyThe label that should appear on the task summary screen if multiple actions are present.no
actions[n].modifyContentfunction (content, contact, report, event)Set the values on the content object to control the data which will be passed as inputs to the form which opens when the action is selected. See Passing data from a task into the app form.no
priorityobject or function(contact, report) returning object of same schemaControls the “high risk” line seen above.no
priority.levelhigh or mediumTasks that are high will display a high risk icon with the task. Default: medium.no
priority.labeltranslation keyText shown with the task associated to the risk level.no

Utils

Utility functions in the Core Framework can make common tasks much easier. These are available only for Tasks and Targets. To use the function call Utils.<function-name>(<params>), for example Utils.addDate(report.reported_date, 10).

NameDescription
isTimely(date, event)Returns true if the given date is after the start date and before the end date of the event.
addDate(date, days)Returns a new Date set to midnight the given number of days after the given date. If no date is given the date defaults to today.
getLmpDate(doc)Attempts to work out the LMP from the given doc. If no LMP is given it defaults to four weeks before the reported_date.
getSchedule(name)Returns the task schedule with the given name from the configuration.
getMostRecentTimestamp(reports, form)Returns the reported_date of the most recent of the reports with form ID matching the given form.
getMostRecentReport(reports, form)Like getMostRecentTimestamp but returns the report, not just the reported_date. From CHT v3.14.0, it also accepts an array of forms.
isFormSubmittedInWindow(reports, form, start, end)Returns true if any of the given reports are for the given form and were reported after start and before end.
isFirstReportNewer(firstReport, secondReport)Returns true if the firstReport was reported before the secondReport.
isDateValid(date)Returns true if the given date is a validate JavaScript Date.
now()Returns the current Date.
getField(report, fieldPath)Returns the value of the specified fieldPath. The fieldPath is a period separated json path.
MS_IN_DAYA constant for the number of milliseconds in a day.

Please open an issue if you’d like other functions included.

CHT API

Introduced in v3.12.0

Provides CHT-Core Framework’s functions to contact summary, targets and tasks. The API is available in the cht reserved variable under the v1 version.

FunctionArgumentsDescription
hasPermissions(permissions, userRoles, chtPermissionsSettings)permissions: String or array of permission name(s).
userRoles: (Optional) Array of user roles. Default to the current logged in user.
chtPermissionsSettings: (Optional) Object of configured permissions in CHT-Core’s settings. Default to the current instance’s configured permissions.
Returns true if the user has the permission(s), otherwise returns false.
hasAnyPermission(permissionsGroups, userRoles, chtPermissionsSettings)permissionsGroups: Array of groups of permission name(s).
userRoles: (Optional) Array of user roles. Default to the current logged in user.
chtPermissionsSettings: (Optional) Object of configured permissions in CHT-Core’s settings. Default to the current instance’s configured permissions.
Returns true if the user has all the permissions of any of the provided groups, otherwise returns false.
getExtensionLib(name)name: String of script nameReturns an executable function identified by the given name configured as extension-libs.

CHT API’s code samples

const canEdit = cht.v1.hasPermissions('can_edit');
const canManagePlaces = cht.v1.hasPermissions(['can_create_places', 'can_update_places']);
const hasAnyGroup = cht.v1.hasAnyPermission([
    ['can_view_messages', 'can_view_message_action'], 
    ['can_view_reports', 'can_verify_reports']
]);
const averageFn = cht.v1.getExtensionLib('average.js');

Code samples

Basic task

This sample tasks.js generates two postnatal-visit tasks for each delivery form. The tasks are due 7 and 14 days after the delivery report was submitted. Each task is displayed for 2 days before the due date and 2 days after the due date.

tasks.js

module.exports = [
  {
    icon: 'mother-child',
    title: 'task.postnatal_followup',
    appliesTo: 'reports',
    appliesToType: [ 'delivery' ],
    actions: [ { form: 'postnatal_visit' } ],
    events: [
      {
        id: 'postnatal-followup-1',
        days:7,
        start:2,
        end:2,
      },
      {
        id: 'postnatal-followup-2',
        days:14, 
        start:2,
        end:2,
      }
    ],
    resolvedIf: function (contact, report, event, dueDate) {
      return Utils.isFormSubmittedInWindow(
        contact.reports,
        'delivery',
        Utils.addDate(dueDate, -event.start).getTime(),
        Utils.addDate(dueDate, event.end + 1).getTime()
      );
    }
  }
];

Tasks with functions

These samples show more complex tasks which use functions kept in a separate nools-extras.js file

tasks.js

const extras = require('./nools-extras');
const { isFormFromArraySubmittedInWindow } = extras;

module.exports = [
  // PNC TASK 1: If a home delivery, needs clinic tasks
  {
    icon: 'mother-child',
    title: 'task.postnatal_followup.title',
    appliesTo: 'reports',
    appliesToType: [ 'D', 'delivery' ],
    appliesIf: function(c, r) {
      return isCoveredByUseCase(c.contact, 'pnc') &&
          r.fields &&
             r.fields.delivery_code &&
             r.fields.delivery_code.toUpperCase() !== 'F';
    },
    actions: [{ 
      form:'postnatal_visit',
      // Pass content that will be used within the task form
      modifyContent: function(content, c, r, event) {
        content.delivery_place = 'home';
        content.event_id = event.id;
      }
    }],
    events: [ {
      id: 'postnatal-visit',
      days:0, start:0, end:4,
    } ],
    priority: {
      level: 'high',
      label: [ { locale:'en', content:'Home Birth' } ],
    },
    resolvedIf: function(c, r, event, dueDate) {
      // Resolved if there a visit report received in time window or a newer pregnancy
      return r.reported_date < extras.getNewestDeliveryTimestamp(c) ||
             r.reported_date < extras.getNewestPregnancyTimestamp(c) ||
             isFormFromArraySubmittedInWindow(c.reports, extras.postnatalForms,
                 Utils.addDate(dueDate, -event.start).getTime(),
                 Utils.addDate(dueDate,  event.end+1).getTime());
    },
  },

  // Option 1a: Place-based task: Family survey when place is created, then every 6 months
  {
    icon: 'family',
    title: 'task.family_survey.title',
    appliesTo: 'contacts',
    appliesToType: [ 'clinic' ],
    actions: [ { form:'family_survey' } ],
    events: [ {
      id: 'family-survey',
      days:0, start:0, end:14,
    } ],
    resolvedIf: function(c, r, event, dueDate) {
      // Resolved if there a family survey received in time window
      return isFormFromArraySubmittedInWindow(c.reports, 'family_survey',
                 Utils.addDate(dueDate, -event.start).getTime(),
                 Utils.addDate(dueDate,  event.end+1).getTime());
    },
  },

  // Regular check for infants
  {
    icon: 'infant',
    title: 'task.infant.title',
    appliesTo: 'contacts',
    appliesToType: [ 'person' ],
    actions: [ { form:'infant_assessment' } ],
    events: [ 
      {
        id: 'infant_asssessment-q1',
        days:91, start:7, end:14,
      },
      {
        id: 'infant_asssessment-q2',
        days:182, start:7, end:14,
      },
      {
        id: 'infant_asssessment-q3',
        days:273, start:7, end:14,
      },
      {
        id: 'infant_asssessment-q4',
        days:365, start:7, end:14,
      }
    ]
  },

  // Option 2: Place-based task: Family survey every 6 months
  {
    icon: 'family',
    title: 'task.family_survey.title',
    appliesTo: 'contacts',
    appliesToType: [ 'clinic' ],
    appliesIf: extras.needsFamilySurvey, // function returns true if family doesn't have survey in previous 6 months
    actions: [ { form:'family_survey' } ],
    events: [ {
      id: 'family-survey',
      start:0, end:14,
      dueDate: extras.getNextFamilySurveyDate  // function gets expected date of next family survey 
    } ],
    resolvedIf: function(c, r, event, dueDate) {
      // Resolved if there a family survey received in time window
      return isFormFromArraySubmittedInWindow(c.reports, 'family_survey',
                 Utils.addDate(dueDate, -event.start).getTime(),
                 Utils.addDate(dueDate,  event.end+1).getTime());
    },
  },

]

nools-extras.js

module.exports = {
  isCoveredByUseCase: function (contact, usecase) {
      // ...
  },
  getNewestDeliveryTimestamp: function (c) {
      // ...
  },
  getNewestPregnancyTimestamp: function (c) {
      // ...
  },
  isFormFromArraySubmittedInWindow: function (reports, formsArray, startTime, endTime) {
      // ...
  },
};

Default resolvedIf method

If the resolvedIf is undefined in an action of type report, then resolvedIf is going to default to defaultResolvedIf method.

The defaultResolvedIf method returns true if it finds any report assigned to the contact that matches the form defined in the action of type report. Only the reports submitted during a specific time period are considered:

  • For a contact-based task, the period is the same as the task window period i.e. when the task is visible.
  • For a report based task, the period is determined between start and end as:
    • start: the latest date between start of the task window and one millisecond after the report’s reported date
    • end: end of the task window

You can also use this.definition.defaultResolvedIf inside the resolvedIf definition and optionally add more conditions:

resolvedIf: function (contact, report, event, dueDate) {
  return this.definition.defaultResolvedIf(contact, report, event, dueDate) && otherConditions;
}

Build

To build your tasks into your app, you must compile them into app-settings, then upload them to your instance.

cht --local compile-app-settings backup-app-settings upload-app-settings


CHT Applications > Features > Tasks

Ensuring that the right actions are taken for the right people at the right time

CHT Applications > Concepts > Workflows

Building connections between people, actions, and data systems

Design System > Best Practices

This document covers the configuration best practices of forms, tasks, targets, and contact profiles when building your own community health app.