Skip to main content

member-ordering

Require a consistent member declaration order.

This rule aims to standardize the way classes, interfaces, and type literals are structured and ordered. A consistent ordering of fields, methods and constructors can make code easier to read, navigate, and edit.

note

This rule is feature frozen: it will no longer receive new features such as new options. It still will accept bug and documentation fixes for its existing area of features.

Stylistic rules that enforce naming and/or sorting conventions tend to grow incomprehensibly complex as increasingly obscure features are requested. This rule has reached the limit of what is reasonable for the typescript-eslint project to maintain. See eslint-plugin: Feature freeze naming and sorting stylistic rules for more information.

.eslintrc.cjs
module.exports = {
  "rules": {
    "@typescript-eslint/member-ordering": "error"
  }
};

Try this rule in the playground ↗

Options​

interface Options {
  default?: OrderConfig;
  classes?: OrderConfig;
  classExpressions?: OrderConfig;
  interfaces?: OrderConfig;
  typeLiterals?: OrderConfig;
}

type OrderConfig = MemberType[] | SortedOrderConfig | 'never';

interface SortedOrderConfig {
  memberTypes?: MemberType[] | 'never';
  optionalityOrder?: 'optional-first' | 'required-first';
  order?:
    | 'alphabetically'
    | 'alphabetically-case-insensitive'
    | 'as-written'
    | 'natural'
    | 'natural-case-insensitive';
}

// See below for the more specific MemberType strings
type MemberType = string | string[];

You can configure OrderConfig options for:

  • default: all constructs (used as a fallback)
  • classes?: override ordering specifically for classes
  • classExpressions?: override ordering specifically for class expressions
  • interfaces?: override ordering specifically for interfaces
  • typeLiterals?: override ordering specifically for type literals

The OrderConfig settings for each kind of construct may configure sorting on up to three levels:

  • memberTypes: organizing on member type groups such as methods vs. properties
  • optionalityOrder: whether to put all optional members first or all required members first
  • order: organizing based on member names, such as alphabetically

Groups​

You can define many different groups based on different attributes of members. The supported member attributes are, in order:

  • Accessibility ('public' | 'protected' | 'private' | '#private')
  • Decoration ('decorated'): Whether the member has an explicit accessibility decorator
  • Kind ('call-signature' | 'constructor' | 'field' | 'readonly-field' | 'get' | 'method' | 'set' | 'signature' | 'readonly-signature')

Member attributes may be joined with a '-' to combine into more specific groups. For example, 'public-field' would come before 'private-field'.

Orders​

The order value specifies what order members should be within a group. It defaults to as-written, meaning any order is fine. Other allowed values are:

  • alphabetically: Sorted in a-z alphabetical order, directly using string < comparison (so B comes before a)
  • alphabetically-case-insensitive: Sorted in a-z alphabetical order, ignoring case (so a comes before B)
  • natural: Same as alphabetically, but using natural-compare-lite for more friendly sorting of numbers
  • natural-case-insensitive: Same as alphabetically-case-insensitive, but using natural-compare-lite for more friendly sorting of numbers

Default configuration​

The default configuration looks as follows:

{
  "default": {
    "memberTypes": [
      // Index signature
      "signature",
      "call-signature",

      // Fields
      "public-static-field",
      "protected-static-field",
      "private-static-field",
      "#private-static-field",

      "public-decorated-field",
      "protected-decorated-field",
      "private-decorated-field",

      "public-instance-field",
      "protected-instance-field",
      "private-instance-field",
      "#private-instance-field",

      "public-abstract-field",
      "protected-abstract-field",

      "public-field",
      "protected-field",
      "private-field",
      "#private-field",

      "static-field",
      "instance-field",
      "abstract-field",

      "decorated-field",

      "field",

      // Static initialization
      "static-initialization",

      // Constructors
      "public-constructor",
      "protected-constructor",
      "private-constructor",

      "constructor",

      // Accessors
      "public-static-accessor",
      "protected-static-accessor",
      "private-static-accessor",
      "#private-static-accessor",

      "public-decorated-accessor",
      "protected-decorated-accessor",
      "private-decorated-accessor",

      "public-instance-accessor",
      "protected-instance-accessor",
      "private-instance-accessor",
      "#private-instance-accessor",

      "public-abstract-accessor",
      "protected-abstract-accessor",

      "public-accessor",
      "protected-accessor",
      "private-accessor",
      "#private-accessor",

      "static-accessor",
      "instance-accessor",
      "abstract-accessor",

      "decorated-accessor",

      "accessor",

      // Getters
      "public-static-get",
      "protected-static-get",
      "private-static-get",
      "#private-static-get",

      "public-decorated-get",
      "protected-decorated-get",
      "private-decorated-get",

      "public-instance-get",
      "protected-instance-get",
      "private-instance-get",
      "#private-instance-get",

      "public-abstract-get",
      "protected-abstract-get",

      "public-get",
      "protected-get",
      "private-get",
      "#private-get",

      "static-get",
      "instance-get",
      "abstract-get",

      "decorated-get",

      "get",

      // Setters
      "public-static-set",
      "protected-static-set",
      "private-static-set",
      "#private-static-set",

      "public-decorated-set",
      "protected-decorated-set",
      "private-decorated-set",

      "public-instance-set",
      "protected-instance-set",
      "private-instance-set",
      "#private-instance-set",

      "public-abstract-set",
      "protected-abstract-set",

      "public-set",
      "protected-set",
      "private-set",
      "#private-set",

      "static-set",
      "instance-set",
      "abstract-set",

      "decorated-set",

      "set",

      // Methods
      "public-static-method",
      "protected-static-method",
      "private-static-method",
      "#private-static-method",

      "public-decorated-method",
      "protected-decorated-method",
      "private-decorated-method",

      "public-instance-method",
      "protected-instance-method",
      "private-instance-method",
      "#private-instance-method",

      "public-abstract-method",
      "protected-abstract-method",

      "public-method",
      "protected-method",
      "private-method",
      "#private-method",

      "static-method",
      "instance-method",
      "abstract-method",

      "decorated-method",

      "method",
    ],
  },
}
note

The default configuration contains member group types which contain other member types. This is intentional to provide better error messages.

tip

By default, the members are not sorted. If you want to sort them alphabetically, you have to provide a custom configuration.

Examples​

General Order on All Constructs​

This config specifies the order for all constructs. It ignores member types other than signatures, methods, constructors, and fields. It also ignores accessibility and scope.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      { "default": ["signature", "method", "constructor", "field"] },
    ],
  },
}
interface Foo {
  B: string; // -> field

  new (); // -> constructor

  A(): void; // -> method

  [Z: string]: any; // -> signature
}
Open in Playground
type Foo = {
  B: string; // -> field

  // no constructor

  A(): void; // -> method

  // no signature
};
Open in Playground
class Foo {
  private C: string; // -> field
  public D: string; // -> field
  protected static E: string; // -> field

  constructor() {} // -> constructor

  public static A(): void {} // -> method
  public B(): void {} // -> method

  [Z: string]: any; // -> signature
}
Open in Playground
const Foo = class {
  private C: string; // -> field
  public D: string; // -> field

  constructor() {} // -> constructor

  public static A(): void {} // -> method
  public B(): void {} // -> method

  [Z: string]: any; // -> signature

  protected static E: string; // -> field
};
Open in Playground

Classes​

Public Instance Methods Before Public Static Fields​

This config specifies that public instance methods should come first before public static fields. Everything else can be placed anywhere. It doesn't apply to interfaces or type literals as accessibility and scope are not part of them.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      { "default": ["public-instance-method", "public-static-field"] },
    ],
  },
}
class Foo {
  private C: string; // (irrelevant)

  public D: string; // (irrelevant)

  public static E: string; // -> public static field

  constructor() {} // (irrelevant)

  public static A(): void {} // (irrelevant)

  [Z: string]: any; // (irrelevant)

  public B(): void {} // -> public instance method
}
Open in Playground
const Foo = class {
  private C: string; // (irrelevant)

  [Z: string]: any; // (irrelevant)

  public static E: string; // -> public static field

  public D: string; // (irrelevant)

  constructor() {} // (irrelevant)

  public static A(): void {} // (irrelevant)

  public B(): void {} // -> public instance method
};
Open in Playground

Static Fields Before Instance Fields​

This config specifies that static fields should come before instance fields, with public static fields first. It doesn't apply to interfaces or type literals as accessibility and scope are not part of them.

{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      { "default": ["public-static-field", "static-field", "instance-field"] },
    ],
  },
}
class Foo {
  private E: string; // -> instance field

  private static B: string; // -> static field
  protected static C: string; // -> static field
  private static D: string; // -> static field

  public static A: string; // -> public static field

  [Z: string]: any; // (irrelevant)
}
Open in Playground
const foo = class {
  public T(): void {} // method (irrelevant)

  private static B: string; // -> static field

  constructor() {} // constructor (irrelevant)

  private E: string; // -> instance field

  protected static C: string; // -> static field
  private static D: string; // -> static field

  [Z: string]: any; // signature (irrelevant)

  public static A: string; // -> public static field
};
Open in Playground

Class Declarations​

This config only specifies an order for classes: methods, then the constructor, then fields. It does not apply to class expressions (use classExpressions for them). Default settings will be used for class declarations and all other syntax constructs other than class declarations.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      { "classes": ["method", "constructor", "field"] },
    ],
  },
}
class Foo {
  private C: string; // -> field
  public D: string; // -> field
  protected static E: string; // -> field

  constructor() {} // -> constructor

  public static A(): void {} // -> method
  public B(): void {} // -> method
}
Open in Playground

Class Expressions​

This config only specifies an order for classes expressions: methods, then the constructor, then fields. It does not apply to class declarations (use classes for them). Default settings will be used for class declarations and all other syntax constructs other than class expressions.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      { "classExpressions": ["method", "constructor", "field"] },
    ],
  },
}
const foo = class {
  private C: string; // -> field
  public D: string; // -> field
  protected static E: string; // -> field

  constructor() {} // -> constructor

  public static A(): void {} // -> method
  public B(): void {} // -> method
};
Open in Playground

Interfaces​

This config only specifies an order for interfaces: signatures, then methods, then constructors, then fields. It does not apply to type literals (use typeLiterals for them). Default settings will be used for type literals and all other syntax constructs other than class expressions.

note

These member types are the only ones allowed for interfaces.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      { "interfaces": ["signature", "method", "constructor", "field"] },
    ],
  },
}
interface Foo {
  B: string; // -> field

  new (); // -> constructor

  A(): void; // -> method

  [Z: string]: any; // -> signature
}
Open in Playground

Type Literals​

This config only specifies an order for type literals: signatures, then methods, then constructors, then fields. It does not apply to interfaces (use interfaces for them). Default settings will be used for interfaces and all other syntax constructs other than class expressions.

note

These member types are the only ones allowed for typeLiterals.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      { "typeLiterals": ["signature", "method", "constructor", "field"] },
    ],
  },
}
type Foo = {
  B: string; // -> field

  A(): void; // -> method

  new (); // -> constructor

  [Z: string]: any; // -> signature
};
Open in Playground

Sorting Options​

Sorting Alphabetically Within Member Groups​

The default member order will be applied if memberTypes is not specified. You can see the default order in Default Configuration.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      {
        "default": {
          "order": "alphabetically",
        },
      },
    ],
  },
}
interface Foo {
  a: x;
  B: x;
  c: x;

  B(): void;
  c(): void;
  a(): void;
}
Open in Playground

Sorting Alphabetically Within Custom Member Groups​

This config specifies that within each custom memberTypes group, members are in an alphabetic case-sensitive order.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      {
        "default": {
          "memberTypes": ["method", "field"],
          "order": "alphabetically",
        },
      },
    ],
  },
}
interface Foo {
  B(): void;
  c(): void;
  a(): void;

  a: x;
  B: x;
  c: x;
}
Open in Playground

Sorting Alphabetically Case Insensitive Within Member Groups​

The default member order will be applied if memberTypes is not specified. You can see the default order in Default Configuration.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      {
        "default": {
          "order": "alphabetically-case-insensitive",
        },
      },
    ],
  },
}
interface Foo {
  B: x;
  a: x;
  c: x;

  B(): void;
  c(): void;
  a(): void;
}
Open in Playground

Sorting Alphabetically Ignoring Member Groups​

This config specifies that members are all sorted in an alphabetic case-sensitive order. It ignores any member group types completely by specifying "never" for memberTypes.

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      { "default": { "memberTypes": "never", "order": "alphabetically" } },
    ],
  },
}
interface Foo {
  b(): void;
  a: boolean;

  [a: string]: number;
  new (): Bar;
  (): Baz;
}
Open in Playground

Sorting Optional Members First or Last​

The optionalityOrder option may be enabled to place all optional members in a group at the beginning or end of that group.

This config places all optional members before all required members:

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      {
        "default": {
          "optionalityOrder": "optional-first",
          "order": "alphabetically",
        },
      },
    ],
  },
}
interface Foo {
  a: boolean;
  b?: number;
  c: string;
}
Open in Playground

This config places all required members before all optional members:

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/member-ordering": [
      "error",
      {
        "default": {
          "optionalityOrder": "required-first",
          "order": "alphabetically",
        },
      },
    ],
  },
}
interface Foo {
  a: boolean;
  b?: number;
  c: string;
}
Open in Playground

All Supported Options​

Member Types (Granular Form)​

There are multiple ways to specify the member types. The most explicit and granular form is the following:

[
  // Index signature
  "signature",
  "readonly-signature",

  // Fields
  "public-static-field",
  "public-static-readonly-field",
  "protected-static-field",
  "protected-static-readonly-field",
  "private-static-field",
  "private-static-readonly-field",
  "#private-static-field",
  "#private-static-readonly-field",

  "public-decorated-field",
  "public-decorated-readonly-field",
  "protected-decorated-field",
  "protected-decorated-readonly-field",
  "private-decorated-field",
  "private-decorated-readonly-field",

  "public-instance-field",
  "public-instance-readonly-field",
  "protected-instance-field",
  "protected-instance-readonly-field",
  "private-instance-field",
  "private-instance-readonly-field",
  "#private-instance-field",
  "#private-instance-readonly-field",

  "public-abstract-field",
  "public-abstract-readonly-field",
  "protected-abstract-field",
  "protected-abstract-readonly-field",

  "public-field",
  "public-readonly-field",
  "protected-field",
  "protected-readonly-field",
  "private-field",
  "private-readonly-field"
  "#private-field",
  "#private-readonly-field"

  "static-field",
  "static-readonly-field",
  "instance-field",
  "instance-readonly-field"
  "abstract-field",
  "abstract-readonly-field",

  "decorated-field",
  "decorated-readonly-field",

  "field",
  "readonly-field",

  // Static initialization
  "static-initialization",

  // Constructors
  "public-constructor",
  "protected-constructor",
  "private-constructor",

  // Getters
  "public-static-get",
  "protected-static-get",
  "private-static-get",
  "#private-static-get",

  "public-decorated-get",
  "protected-decorated-get",
  "private-decorated-get",

  "public-instance-get",
  "protected-instance-get",
  "private-instance-get",
  "#private-instance-get",

  "public-abstract-get",
  "protected-abstract-get",

  "public-get",
  "protected-get",
  "private-get",
  "#private-get",

  "static-get",
  "instance-get",
  "abstract-get",

  "decorated-get",

  "get",

  // Setters
  "public-static-set",
  "protected-static-set",
  "private-static-set",
  "#private-static-set",

  "public-decorated-set",
  "protected-decorated-set",
  "private-decorated-set",

  "public-instance-set",
  "protected-instance-set",
  "private-instance-set",
  "#private-instance-set",

  "public-abstract-set",
  "protected-abstract-set",

  "public-set",
  "protected-set",
  "private-set",

  "static-set",
  "instance-set",
  "abstract-set",

  "decorated-set",

  "set",

  // Methods
  "public-static-method",
  "protected-static-method",
  "private-static-method",
  "#private-static-method",
  "public-decorated-method",
  "protected-decorated-method",
  "private-decorated-method",
  "public-instance-method",
  "protected-instance-method",
  "private-instance-method",
  "#private-instance-method",
  "public-abstract-method",
  "protected-abstract-method"
]
note

If you only specify some of the possible types, the non-specified ones can have any particular order. This means that they can be placed before, within or after the specified types and the linter won't complain about it.

Member Group Types (With Accessibility, Ignoring Scope)​

It is also possible to group member types by their accessibility (static, instance, abstract), ignoring their scope.

[
  // Index signature
  // No accessibility for index signature.

  // Fields
  "public-field", // = ["public-static-field", "public-instance-field"]
  "protected-field", // = ["protected-static-field", "protected-instance-field"]
  "private-field", // = ["private-static-field", "private-instance-field"]

  // Static initialization
  // No accessibility for static initialization.

  // Constructors
  // Only the accessibility of constructors is configurable. See below.

  // Getters
  "public-get", // = ["public-static-get", "public-instance-get"]
  "protected-get", // = ["protected-static-get", "protected-instance-get"]
  "private-get", // = ["private-static-get", "private-instance-get"]

  // Setters
  "public-set", // = ["public-static-set", "public-instance-set"]
  "protected-set", // = ["protected-static-set", "protected-instance-set"]
  "private-set", // = ["private-static-set", "private-instance-set"]

  // Methods
  "public-method", // = ["public-static-method", "public-instance-method"]
  "protected-method", // = ["protected-static-method", "protected-instance-method"]
  "private-method", // = ["private-static-method", "private-instance-method"]
]

Member Group Types (With Accessibility and a Decorator)​

It is also possible to group methods or fields with a decorator separately, optionally specifying their accessibility.

[
  // Index signature
  // No decorators for index signature.

  // Fields
  "public-decorated-field",
  "protected-decorated-field",
  "private-decorated-field",

  "decorated-field", // = ["public-decorated-field", "protected-decorated-field", "private-decorated-field"]

  // Static initialization
  // No decorators for static initialization.

  // Constructors
  // There are no decorators for constructors.

  // Getters
  "public-decorated-get",
  "protected-decorated-get",
  "private-decorated-get",

  "decorated-get", // = ["public-decorated-get", "protected-decorated-get", "private-decorated-get"]

  // Setters
  "public-decorated-set",
  "protected-decorated-set",
  "private-decorated-set",

  "decorated-set", // = ["public-decorated-set", "protected-decorated-set", "private-decorated-set"]

  // Methods
  "public-decorated-method",
  "protected-decorated-method",
  "private-decorated-method",

  "decorated-method", // = ["public-decorated-method", "protected-decorated-method", "private-decorated-method"]
]

Member Group Types (With Scope, Ignoring Accessibility)​

Another option is to group the member types by their scope (public, protected, private), ignoring their accessibility.

[
  // Index signature
  // No scope for index signature.

  // Fields
  "static-field", // = ["public-static-field", "protected-static-field", "private-static-field"]
  "instance-field", // = ["public-instance-field", "protected-instance-field", "private-instance-field"]
  "abstract-field", // = ["public-abstract-field", "protected-abstract-field"]

  // Static initialization
  // No scope for static initialization.

  // Constructors
  "constructor", // = ["public-constructor", "protected-constructor", "private-constructor"]

  // Getters
  "static-get", // = ["public-static-get", "protected-static-get", "private-static-get"]
  "instance-get", // = ["public-instance-get", "protected-instance-get", "private-instance-get"]
  "abstract-get", // = ["public-abstract-get", "protected-abstract-get"]

  // Setters
  "static-set", // = ["public-static-set", "protected-static-set", "private-static-set"]
  "instance-set", // = ["public-instance-set", "protected-instance-set", "private-instance-set"]
  "abstract-set", // = ["public-abstract-set", "protected-abstract-set"]

  // Methods
  "static-method", // = ["public-static-method", "protected-static-method", "private-static-method"]
  "instance-method", // = ["public-instance-method", "protected-instance-method", "private-instance-method"]
  "abstract-method", // = ["public-abstract-method", "protected-abstract-method"]
]

Member Group Types (With Scope and Accessibility)​

The third grouping option is to ignore both scope and accessibility.

[
  // Index signature
  // No grouping for index signature.

  // Fields
  "field", // = ["public-static-field", "protected-static-field", "private-static-field", "public-instance-field", "protected-instance-field", "private-instance-field",
  //              "public-abstract-field", "protected-abstract-field"]

  // Static initialization
  // No grouping for static initialization.

  // Constructors
  // Only the accessibility of constructors is configurable.

  // Getters
  "get", // = ["public-static-get", "protected-static-get", "private-static-get", "public-instance-get", "protected-instance-get", "private-instance-get",
  //                "public-abstract-get", "protected-abstract-get"]

  // Setters
  "set", // = ["public-static-set", "protected-static-set", "private-static-set", "public-instance-set", "protected-instance-set", "private-instance-set",
  //                "public-abstract-set", "protected-abstract-set"]

  // Methods
  "method", // = ["public-static-method", "protected-static-method", "private-static-method", "public-instance-method", "protected-instance-method", "private-instance-method",
  //                "public-abstract-method", "protected-abstract-method"]
]

Member Group Types (Readonly Fields)​

It is possible to group fields by their readonly modifiers.

[
  // Index signature
  "readonly-signature",
  "signature",

  // Fields
  "readonly-field", // = ["public-static-readonly-field", "protected-static-readonly-field", "private-static-readonly-field", "public-instance-readonly-field", "protected-instance-readonly-field", "private-instance-readonly-field", "public-abstract-readonly-field", "protected-abstract-readonly-field"]
  "field", // = ["public-static-field", "protected-static-field", "private-static-field", "public-instance-field", "protected-instance-field", "private-instance-field", "public-abstract-field", "protected-abstract-field"]
]

Grouping Different Member Types at the Same Rank​

It is also possible to group different member types at the same rank.

[
  // Index signature
  "signature",

  // Fields
  "field",

  // Static initialization
  "static-initialization",

  // Constructors
  "constructor",

  // Getters and Setters at the same rank
  ["get", "set"],

  // Methods
  "method",
]

When Not To Use It​

If you don't care about the general order of your members, then you will not need this rule.

Resources​