airbnb/javascript: JavaScript Style Guide

User Object Cheat Sheet
N

o matter what system you’re working in, it is always critical to be able to identify information about the user who is accessing that system. Being able to identify who the user is, what their groups and/or roles are, and what other attributes their user record has are all important pieces of information that allow you to provide that user with a good experience (without giving them information they don’t need to have or shouldn’t have). ServiceNow gives administrators some pretty simple ways to identify this information in the form of a couple of user objects and corresponding methods. This article describes the functions and methods you can use to get information about the users accessing your system.



GlideSystem User Object

The GlideSystem (gs) user object is designed to be used in any server-side JavaScript (Business rules, UI Actions, System security, etc.). The following table shows how to use this object and its corresponding functions and methods.

Function/Method	Return Value	Usage
gs.getUser()	Returns a reference to the user object for the currently logged-in user.	var userObject = gs.getUser();
gs.getUserByID()	Returns a reference to the user object for the user ID (or sys_id) provided.	var userObject = gs.getUser().getUserByID('employee');
gs.getUserName()	Returns the User ID (user_name) for the currently logged-in user.
e.g. 'employee'	var user_name = gs.getUserName();
gs.getUserDisplayName()	Returns the display value for the currently logged-in user.
e.g. 'Joe Employee'	var userDisplay = gs.getUserDisplayName();
gs.getUserID()	Returns the sys_id string value for the currently logged-in user.	var userID = gs.getUserID();
getFirstName()	Returns the first name of the currently logged-in user.	var firstName = gs.getUser().getFirstName();
getLastName()	Returns the last name of the currently logged-in user.	var lastName = gs.getUser().getLastName();
getEmail()	Returns the email address of the currently logged-in user.	var email = gs.getUser().getEmail();
getDepartmentID()	Returns the department sys_id of the currently logged-in user.	var deptID = gs.getUser().getDepartmentID();
getCompanyID()	Returns the company sys_id of the currently logged-in user.	var companyID = gs.getUser().getCompanyID();
getCompanyRecord()	Returns the company GlideRecord of the currently logged-in user.	var company = gs.getUser().getCompanyRecord();
getLanguage()	Returns the language of the currently logged-in user.	var language = gs.getUser().getLanguage();
getLocation()	Returns the location of the currently logged-in user.	var location = gs.getUser().getLocation();
getDomainID()	Returns the domain sys_id of the currently logged-in user (only used for instances using domain separation).	var domainID = gs.getUser().getDomainID();
getDomainDisplayValue()	Returns the domain display value of the currently logged-in user (only used for instances using domain separation).	var domainName = gs.getUser().getDomainDisplayValue();
getManagerID()	Returns the manager sys_id of the currently logged-in user.	var managerID = gs.getUser().getManagerID();
getMyGroups()	Returns a list of all groups that the currently logged-in user is a member of.	var groups = gs.getUser().getMyGroups();
isMemberOf()	Returns true if the user is a member of the given group, false otherwise.	Takes either a group sys_id or a group name as an argument.

if(gs.getUser().isMemberOf(current.assignment_group)){
//Do something...
}

var isMember = gs.getUser().isMemberOf('Hardware');

To do this for a user that isn't the currently logged-in user...

var user = 'admin';
var group = "Hardware";
if (gs.getUser().getUserByID(user).isMemberOf(group)){
gs.log( gr.user_name + " is a member of " + group);
}

else{
gs.log( gr.user_name + " is NOT a member of " + group);
}
gs.hasRole()	Returns true if the user has the given role, false otherwise.	if(gs.hasRole('itil')){ //Do something... }
gs.hasRole()	Returns true if the user has one of the given roles, false otherwise.	if(gs.hasRole('itil,admin')){
//If user has 'itil' OR 'admin' role then Do something...
}
hasRoles()	Returns true if the user has any roles at all, false if the user has no role (i.e. an ess user).	if(!gs.getUser().hasRoles()){
//User is an ess user...
}
It is also very simple to get user information even if the attribute you want to retrieve is not listed above by using a ‘gs.getUser().getRecord()’ call as shown here…

//This script gets the user's title
gs.getUser().getRecord().getValue('title');


g_user User Object

The g_user object can be used only in UI policies and Client scripts. Contrary to its naming, it is not truly a user object. g_user is actually just a handful of cached user properties that are accessible to client-side JavaScript. This eliminates the need for most GlideRecord queries from the client to get user information (which can incur a fairly significant performance hit if not used judiciously).

g_user Property or Method	Return value
g_user.userName	User name of the current user e.g. employee
g_user.firstName	First name of the current user e.g. Joe
g_user.lastName	Last name of the current user e.g. Employee
g_user.userID	sys_id of the current user e.g. 681ccaf9c0a8016400b98a06818d57c7
g_user.hasRole()	True if the current user has the role specified, false otherwise. ALWAYS returns true if the user has the 'admin' role.

Usage: g_user.hasRole('itil')
g_user.hasRoleExactly()	True if the current user has the exact role specified, false otherwise, regardless of 'admin' role.

Usage: g_user.hasRoleExactly('itil')
g_user.hasRoles()	True if the current user has at least one role specified, false otherwise.

Usage: g_user.hasRoles('itil','admin')
It is often necessary to determine if a user is a member of a given group from the client as well. Although there is no convenience method for determining this from the client, you can get the information by performing a GlideRecord query. Here’s an example…

//Check to see if assigned to is a member of selected group
var grpName = 'YOURGROUPNAMEHERE';
var usrID = g_form.userID; //Get current user ID
var grp = new GlideRecord('sys_user_grmember');
grp.addQuery('group.name', grpName);
grp.addQuery('user', usrID);
grp.query(groupMemberCallback);
   
function groupMemberCallback(grp){
//If user is a member of selected group
    if(grp.next()){
        //Do something
        alert('Is a member');
    }
    else{
        alert('Is not a member');
    }
}
To get any additional information about the currently logged-in user from a client-script or UI policy, you need to use a GlideRecord query. If at all possible, you should use a server-side technique described above since GlideRecord queries can have performance implications when initiated from a client script. For the situations where there’s no way around it, you could use a script similar to the one shown below to query from the client for more information about the currently logged in user.

//This script gets the user's title
var gr = new GlideRecord('sys_user');
gr.get(g_user.userID);
var title = gr.title;
alert(title);


Useful Scripts

There are quite a few documented examples of some common uses of these script methods. These scripts can be found on the ServiceNow wiki.

import React, { Component } from "react";

class IconList extends Component {
  static defaultProps = {
    options: [
      "angry",
      "anchor",
      "archive",
      "at",
      "archway",
      "baby",
      "bell",
      "bolt",
      "bone",
      "car",
      "city",
      "cloud",
      "couch"
    ]
  };
  constructor(props) {
    super(props);
    this.state = { icons: ["bone", "cloud"] };
    this.addIcon = this.addIcon.bind(this);
  }
  //DON'T DO THIS!!!!
  // addIcon() {
  //   let idx = Math.floor(Math.random() * this.props.options.length);
  //   let newIcon = this.props.options[idx];
  //   let icons = this.state.icons;
  //   icons.push(newIcon);
  //   this.setState({ icons: icons });
  // }

  addIcon() {
    // get random index
    let idx = Math.floor(Math.random() * this.props.options.length);
 	// get new element
    let newIcon = this.props.options[idx];
    // update the state of the icons array (spread icons into new array, add new icon to it)
    this.setState({ icons: [...this.state.icons, newIcon] });
  }
  render() {
    // render newly mapped icons array
    const icons = this.state.icons.map(i => <i className={`fas fa-${i}`} />);
    return (
      <div>
        <h1>Icons: {icons}</h1>
        <button onClick={this.addIcon}>Add New Icon</button>
      </div>
    );
  }
}

export default IconList;

//What are pure functions?
//Pure functions take an input value (a parameter or argument) and produce an output value. //Like with hashing, the same input it will always return the same output 

const myPureFunction = number => return number * 4

//Pure functions must:
//1. Contain no side effects
//2. When given the same input, return the same output.
// A pure component avoids any use of state.
map
filter
reduce

// This is what I've been using, pretty straight forward
// It passes the JSON to the children as props
// Of course, you fetch what you will
 
import React, { Component, Fragment } from 'react';
 
export class FetchJsonController extends Component
{
	constructor(props) {
		super(props);
		this.state = {
			data: null,
		};
	}
 
	componentDidMount() {
		fetch(this.props.src)
			.then(response => response.json())
			.then(data => {
				console.log(data);
				this.setState({ data })
			});
	}
 
	render() {
		const _data = this.state.data;
		const children = React.Children.map(this.props.children, child => {
			return React.cloneElement(child, {
				jsonData: _data
			});
		});
		return (
			<div>{ children }</div>
		)
	}
}
 
// This is how it's used
// SomeCompnent will receive the JSON data
<FetchJsonController src="somefile.json">
  <SomeComponent />
</FetchJsonController>

// bad
function getFullName(user) {
  const firstName = user.firstName;
  const lastName = user.lastName;

  return `${firstName} ${lastName}`;
}

// good
function getFullName(user) {
  const { firstName, lastName } = user;
  return `${firstName} ${lastName}`;
}

// best
function getFullName({ firstName, lastName }) {
  return `${firstName} ${lastName}`;
}

const todo = {
  id: 1,
  firstName: "David",
  lastName: "Mchale",
  age: 40,
  user: {
    isLoggedIn: false,
  },
};


// using curly braces means we are destructuring
// NOT using curly braces and using ':' means we are just renaming

const {
  id: position, // renaming
  firstName,
  lastName,
  age,
  user: { isLoggedIn }, // getting the value from the user isLoggedIn
} = todo;
console.log("destructure => ", firstName, lastName, age, isLoggedIn, position);

const myObject= {
  'Age': '25',
  'Gender': 'Male',
  'Nationality': 'Australian'
};

const myMap = new Map(Object.entries(myObject)); //object to map
const anotherObject = Object.fromEntries(myMap) // map to object

let sizes = cars.map(car => {
  if (car.capacity <= 3){
    return "small";
  }
  if (car.capacity <= 5){
    return "medium";
  }
  return "large";
});
console.log(sizes);
// output:
// ['large','medium','medium', ..., 'small']

//create a new object if we need more values:

let carsProperties = cars.map(car => {
 let properties = {
   "capacity": car.capacity,
   "size": "large"
 };
 if (car.capacity <= 5){
   properties['size'] = "medium";
 }
 if (car.capacity <= 3){
   properties['size'] = "small";
 }
 return properties;
});
console.log(carsProperties);
// output:
// [
//   { capacity: 7, size: 'large' },
//   { capacity: 5, size: 'medium' },
//   { capacity: 5, size: 'medium' },
//   { capacity: 2, size: 'small' },
//   ...
// ]

cars.forEach(car => {
 car['size'] = "large";
 if (car.capacity <= 5){
   car['size'] = "medium";
 }
 if (car.capacity <= 3){
   car['size'] = "small";
 }
});

cars.forEach(car => {
 car['size'] = "large";
 if (car.capacity <= 5){
   car['size'] = "medium";
 }
 if (car.capacity <= 3){
   car['size'] = "small";
 }
});

let sortedCars = cars.sort((c1, c2) => (c1.capacity < c2.capacity) ? 1 : (c1.capacity > c2.capacity) ? -1 : 0);
console.log(sortedCars);
// output:
// [
//   {
//     color: 'purple',
//     type: 'minivan',
//     registration: 'Wed Feb 01 2017 00:00:00 GMT+0100 (GMT+01:00)',
//     capacity: 7
//   },
//   {
//     color: 'red',
//     type: 'station wagon',
//     registration: 'Sat Mar 03 2018 01:00:00 GMT+0100 (GMT+01:00)',
//     capacity: 5
//   },
//   ...
// ]

cars.some(car => car.color === "red" && car.type === "cabrio");
// output: true

cars.every(car => car.capacity >= 4);
// output: false

function getKey(k) {
  return `a key named ${k}`;
}

// bad
const obj = {
  id: 5,
  name: 'San Francisco',
};
obj[getKey('enabled')] = true;

// good
const obj = {
  id: 5,
  name: 'San Francisco',
  [getKey('enabled')]: true,
};

const person = {
  name: 'Sam',
  age: 300,
}

const twinPerson = {
  ...person
}