Maxi ContieriDo you need help? Who are you gonna call?
TL;DR: Helpers don't help. They are a non cohesive bunch of messy subrutines.
Problems
Readability
The Least surprise principle
Bijection Fault
Static methods
Solutions
Find a suitable name
If the helper is a library, break all the services as different methods.
Methods should always be fulfilled by objects. Static methods are another code smell.
Avoid extracting the helpers to Anonymous Functions.
Sample Code
Wrong
export default class UserHelpers {
static getFullName(user) {
return `${user.firstName} ${user.lastName}`;
}
static getCategory(userPoints) {
return userPoints > 70 ? 'A' : 'B';
}
}
Notice static methods.
import UserHelpers from './UserHelpers';
const alice = {
firstName: 'Alice',
lastName: 'Gray',
points: 78,
};
const fullName = UserHelpers.getFullName(alice);
const category = UserHelpers.getCategory(alice);
Right
class UserScore {
//This is anemic class and should have better protocol
constructor(name, lastname, points) {
this._name = name;
this._lastname = lastname;
this._points = points;
}
name(){
return this._name;
}
lastname(){
return this._lastname;
}
points(){
return this._points;
}
}
class FullNameFormatter {
constructor(userscore) {
this._userscore = userscore;
}
fullname() {
return `${this._userscore.name()} ${this._userscore.lastname()}`;
}
}
class CategoryCalculator{
constructor(userscore1){
this._userscore = userscore1;
}
display() {
return this._userscore.points() > 70 ? 'A' : 'B';
}
}
let alice = new UserScore('Alice', 'Gray', 78);
const fullName = new FullNameFormatter(alice).fullname();
const category = new CategoryCalculator(alice).display();
or we can make the former Helper stateless for reuse...
class UserScore {
//This is anemic class and should have better protocol
constructor(name, lastname, points) {
this._name = name;
this._lastname = lastname;
this._points = points;
}
name(){
return this._name;
}
lastname(){
return this._lastname;
}
points(){
return this._points;
}
}
class FullNameFormatter {
fullname(userscore) {
return `${userscore.name()} ${userscore.lastname()}`;
}
}
class CategoryCalculator{
display(userscore) {
return userscore.points() > 70 ? 'A' : 'B';
}
}
let alice = new UserScore('Alice', 'Gray', 78);
const fullName = new FullNameFormatter().fullname(alice);
const category = new CategoryCalculator().display(alice);
Detection
- Code naming standards should forbid classes with this name on them.
Tags
- Namings
Conclusion
This is a well established cultural name and a legacy habit from structured programming.
Most developers are reluctant to let old habits go.
We must be aware of the damage this kind of names are bringing us.
Relations
Also known as
- Utils
More Info
This article is part of the CodeSmell Series.
Last update: 2021/07/04
