Require explicit accessibility modifiers on class properties and methods (explicit-member-accessibility)
Leaving off accessibility modifier and making everything public can make your interface hard to use by others. If you make all internal pieces private or protected, your interface will be easier to use.
This rule aims to make code more readable and explicit about who can use which properties.
type AccessibilityLevel =
| 'explicit' // require an accessor (including public)
| 'no-public' // don't require public
| 'off'; // don't check
interface Config {
accessibility?: AccessibilityLevel;
overrides?: {
accessors?: AccessibilityLevel;
constructors?: AccessibilityLevel;
methods?: AccessibilityLevel;
properties?: AccessibilityLevel;
parameterProperties?: AccessibilityLevel;
};
}
Default config:
{ "accessibility": "explicit" }
This rule in it's default state requires no configuration and will enforce that every class member has an accessibility modifier. If you would like to allow for some implicit public members then you have the following options: A possible configuration could be:
{
accessibility: 'explicit',
overrides: {
accessors: 'explicit',
constructors: 'no-public',
methods: 'explicit',
properties: 'off',
parameterProperties: 'explicit'
}
}
The following patterns are considered incorrect code if no options are provided:
class Animal {
constructor(name) {
// No accessibility modifier
this.animalName = name;
}
animalName: string; // No accessibility modifier
get name(): string {
// No accessibility modifier
return this.animalName;
}
set name(value: string) {
// No accessibility modifier
this.animalName = value;
}
walk() {
// method
}
}
The following patterns are considered correct with the default options { accessibility: 'explicit' }
:
class Animal {
public constructor(public breed, animalName) {
// Parameter property and constructor
this.animalName = name;
}
private animalName: string; // Property
get name(): string {
// get accessor
return this.animalName;
}
set name(value: string) {
// set accessor
this.animalName = value;
}
public walk() {
// method
}
}
The following patterns are considered incorrect with the accessibility set to no-public [{ accessibility: 'no-public' }]
:
class Animal {
public constructor(public breed, animalName) {
// Parameter property and constructor
this.animalName = name;
}
public animalName: string; // Property
public get name(): string {
// get accessor
return this.animalName;
}
public set name(value: string) {
// set accessor
this.animalName = value;
}
public walk() {
// method
}
}
The following patterns are considered correct with the accessibility set to no-public [{ accessibility: 'no-public' }]
:
class Animal {
constructor(protected breed, animalName) {
// Parameter property and constructor
this.name = name;
}
private animalName: string; // Property
get name(): string {
// get accessor
return this.animalName;
}
private set name(value: string) {
// set accessor
this.animalName = value;
}
protected walk() {
// method
}
}
There are three ways in which an override can be used.
- To disallow the use of public on a given member.
- To enforce explicit member accessibility when the root has allowed implicit public accessibility
- To disable any checks on given member type
e.g. [ { overrides: { constructor: 'no-public' } } ]
The following patterns are considered incorrect with the example override
class Animal {
public constructor(protected animalName) {}
public get name() {
return this.animalName;
}
}
The following patterns are considered correct with the example override
class Animal {
constructor(protected animalName) {}
public get name() {
return this.animalName;
}
}
e.g. [ { accessibility: 'no-public', overrides: { properties: 'explicit' } } ]
The following patterns are considered incorrect with the example override
class Animal {
constructor(protected animalName) {}
get name() {
return this.animalName;
}
protected set name(value: string) {
this.animalName = value;
}
legs: number;
private hasFleas: boolean;
}
The following patterns are considered correct with the example override
class Animal {
constructor(protected animalName) {}
get name() {
return this.animalName;
}
protected set name(value: string) {
this.animalName = value;
}
public legs: number;
private hasFleas: boolean;
}
e.g. [{ overrides: { accessors : 'off' } } ]
As no checks on the overridden member type are performed all permutations of visibility are permitted for that member type
The follow pattern is considered incorrect for the given configuration
class Animal {
constructor(protected animalName) {}
public get name() {
return this.animalName;
}
get legs() {
return this.legCount;
}
}
The following patterns are considered correct with the example override
class Animal {
public constructor(protected animalName) {}
public get name() {
return this.animalName;
}
get legs() {
return this.legCount;
}
}
If you think defaulting to public is a good default, then you should consider using the no-public
setting. If you want to mix implicit and explicit public members then disable this rule.
- TypeScript Accessibility Modifiers
- TSLint: member-access