typescript-eslint · bradzacher · Jan 13, 2020 · Dec 9, 2019 · Dec 9, 2019 · Dec 9, 2019
diff --git a/.cspell.json b/.cspell.json
@@ -9,7 +9,8 @@
     "**/**/CHANGELOG.md",
     "**/**/CONTRIBUTORS.md",
     "**/**/ROADMAP.md",
-    "**/*.{json,snap}"
+    "**/*.{json,snap}",
+    ".cspell.json"
   ],
   "dictionaries": [
     "typescript",
@@ -54,6 +55,8 @@
     "destructure",
     "destructured",
     "erroring",
+    "ESLint",
+    "ESLint's",
     "espree",
     "estree",
     "linebreaks",

diff --git a/packages/eslint-plugin/README.md b/packages/eslint-plugin/README.md
@@ -101,20 +101,16 @@ Pro Tip: For larger codebases you may want to consider splitting our linting int
 | [`@typescript-eslint/ban-ts-ignore`](./docs/rules/ban-ts-ignore.md)                                       | Bans “// @ts-ignore” comments from being used                                                                                                       | :heavy_check_mark: |          |                   |
 | [`@typescript-eslint/ban-types`](./docs/rules/ban-types.md)                                               | Bans specific types from being used                                                                                                                 | :heavy_check_mark: | :wrench: |                   |
 | [`@typescript-eslint/brace-style`](./docs/rules/brace-style.md)                                           | Enforce consistent brace style for blocks                                                                                                           |                    | :wrench: |                   |
-| [`@typescript-eslint/camelcase`](./docs/rules/camelcase.md)                                               | Enforce camelCase naming convention                                                                                                                 | :heavy_check_mark: |          |                   |
-| [`@typescript-eslint/class-name-casing`](./docs/rules/class-name-casing.md)                               | Require PascalCased class and interface names                                                                                                       | :heavy_check_mark: |          |                   |
 | [`@typescript-eslint/consistent-type-assertions`](./docs/rules/consistent-type-assertions.md)             | Enforces consistent usage of type assertions                                                                                                        | :heavy_check_mark: |          |                   |
 | [`@typescript-eslint/consistent-type-definitions`](./docs/rules/consistent-type-definitions.md)           | Consistent with type definition either `interface` or `type`                                                                                        |                    | :wrench: |                   |
 | [`@typescript-eslint/default-param-last`](./docs/rules/default-param-last.md)           | Enforce default parameters to be last                                                                                        |                    | |                   |
 | [`@typescript-eslint/explicit-function-return-type`](./docs/rules/explicit-function-return-type.md)       | Require explicit return types on functions and class methods                                                                                        | :heavy_check_mark: |          |                   |
 | [`@typescript-eslint/explicit-member-accessibility`](./docs/rules/explicit-member-accessibility.md)       | Require explicit accessibility modifiers on class properties and methods                                                                            |                    |          |                   |
 | [`@typescript-eslint/func-call-spacing`](./docs/rules/func-call-spacing.md)                               | Require or disallow spacing between function identifiers and their invocations                                                                      |                    | :wrench: |                   |
-| [`@typescript-eslint/generic-type-naming`](./docs/rules/generic-type-naming.md)                           | Enforces naming of generic type variables                                                                                                           |                    |          |                   |
 | [`@typescript-eslint/indent`](./docs/rules/indent.md)                                                     | Enforce consistent indentation                                                                                                                      |                    | :wrench: |                   |
-| [`@typescript-eslint/interface-name-prefix`](./docs/rules/interface-name-prefix.md)                       | Require that interface names should or should not prefixed with `I`                                                                                 | :heavy_check_mark: |          |                   |
 | [`@typescript-eslint/member-delimiter-style`](./docs/rules/member-delimiter-style.md)                     | Require a specific member delimiter style for interfaces and type literals                                                                          | :heavy_check_mark: | :wrench: |                   |
-| [`@typescript-eslint/member-naming`](./docs/rules/member-naming.md)                                       | Enforces naming conventions for class members by visibility                                                                                         |                    |          |                   |
 | [`@typescript-eslint/member-ordering`](./docs/rules/member-ordering.md)                                   | Require a consistent member declaration order                                                                                                       |                    |          |                   |
+| [`@typescript-eslint/naming-convention`](./docs/rules/naming-convention.md)                               | Enforces naming conventions for everything across a codebase                                                                                        |                    |          | :thought_balloon: |
 | [`@typescript-eslint/no-array-constructor`](./docs/rules/no-array-constructor.md)                         | Disallow generic `Array` constructors                                                                                                               | :heavy_check_mark: | :wrench: |                   |
 | [`@typescript-eslint/no-dynamic-delete`](./docs/rules/no-dynamic-delete.md)                               | Disallow the delete operator with computed key expressions                                                                                          |                    | :wrench: |                   |
 | [`@typescript-eslint/no-empty-function`](./docs/rules/no-empty-function.md)                               | Disallow empty functions                                                                                                                            | :heavy_check_mark: |          |                   |

diff --git a/packages/eslint-plugin/docs/rules/naming-convention.md b/packages/eslint-plugin/docs/rules/naming-convention.md
@@ -0,0 +1,338 @@
+# Enforces naming conventions for everything across a codebase (`naming-convention`)
+
+Enforcing naming conventions helps keep the codebase consistent, and reduces overhead when thinking about how to name a variable.
+Additionally, a well designed style guide can help communicate intent, such as by enforcing all private properties begin with an `_`, and all global-level constants are written in `UPPER_CASE`.
+
+There are many different rules that have existed over time, but they have had the problem of not having enough granularity, meaning it was hard to have a well defined style guide, and most of the time you needed 3 or more rules at once to enforce different conventions, hoping they didn't conflict.
+
+## Rule Details
+
+This rule allows you to enforce conventions for any identifier, using granular selectors to create a fine-grained style guide.
+
+### Note - this rule only needs type information in specific cases, detailed below
+
+## Options
+
+This rule accepts an array of objects, with each object describing a different naming convention.
+Each property will be described in detail below. Also see the examples section below for illustrated examples.
+
+```ts
+type Options = {
+  // format options
+  format: (
+    | 'camelCase'
+    | 'strictCamelCase'
+    | 'PascalCase'
+    | 'StrictPascalCase'
+    | 'snake_case'
+    | 'UPPER_CASE'
+  )[];
+  custom?: {
+    regex: string;
+    match: boolean;
+  };
+  leadingUnderscore?: 'forbid' | 'allow' | 'require';
+  trailingUnderscore?: 'forbid' | 'allow' | 'require';
+  prefix?: string[];
+  suffix?: string[];
+
+  // selector options
+  selector: Selector;
+  filter?: string;
+  // the allowed values for these are dependent on the selector - see below
+  modifiers?: Modifiers<Selector>[];
+  types?: Types<Selector>[];
+}[];
+
+// the default config essentially does the same thing as ESLint's camelcase rule
+const defaultOptions: Options = [
+  {
+    selector: 'default',
+    format: ['camelCase'],
+    leadingUnderscore: 'allow',
+    trailingUnderscore: 'allow',
+  },
+
+  {
+    selector: 'variable',
+    format: ['camelCase', 'UPPER_CASE'],
+    leadingUnderscore: 'allow',
+    trailingUnderscore: 'allow',
+  },
+
+  {
+    selector: 'typeLike',
+    format: ['PascalCase'],
+  },
+];
+```
+
+### Format Options
+
+Every single selector can have the same set of format options.
+When the format of an identifier is checked, it is checked in the following order:
+
+1. validate leading underscore
+1. validate trailing underscore
+1. validate prefix
+1. validate suffix
+1. validate custom
+1. validate format
+
+At each step, if the identifier matches the option, the matching part will be removed.
+For example, if you provide the following formatting option: `{ leadingUnderscore: 'allow', prefix: ['I'], format: ['StrictPascalCase'] }`, for the identifier `_IMyInterface`, then the following checks will occur:
+
+1. `name = _IMyInterface`
+1. validate leading underscore - pass
+   - Trim leading underscore - `name = IMyInterface`
+1. validate trailing underscore - no check
+1. validate prefix - pass
+   - Trim prefix - `name = MyInterface`
+1. validate suffix - no check
+1. validate format - pass
+
+One final note is that if the name were to become empty via this trimming process, it is considered to match all `format`s. An example of where this might be useful is for generic type parameters, where you want all names to be prefixed with `T`, but also want to allow for the single character `T` name.
+
+#### `format`
+
+The `format` option defines the allowed formats for the identifier. This option accepts an array of the following values, and the identifier can match any of them:
+
+- `camelCase` - standard camelCase format - no underscores are allowed between characters, and consecutive capitals are allowed (i.e. both `myID` and `myId` are valid).
+- `strictCamelCase` - same as `camelCase`, but consecutive capitals are not allowed (i.e. `myId` is valid, but `myID` is not).
+- `PascalCase` - same as `camelCase`, except the first character must be upper-case.
+- `StrictPascalCase` - same as `strictCamelCase`, except the first character must be upper-case.
+- `snake_case` - standard snake_case format - all characters must be lower-case, and underscores are allowed.
+- `UPPER_CASE` - same as `snake_case`, except all characters must be upper-case.
+
+### `custom`
+
+The `custom` option defines a custom regex that the identifier must (or must not) match. This option allows you to have a bit more finer-grained control over identifiers, letting you ban (or force) certain patterns and substrings.
+Accepts an object with the following properties:
+
+- `regex` - accepts a regular expression (anything accepted into `new RegExp(filter)`).
+- `match` - true if the identifier _must_ match the `regex`, false if the identifier _must not_ match the `regex`.
+
+#### `leadingUnderscore` / `trailingUnderscore`
+
+The `leadingUnderscore` / `trailingUnderscore` options control whether leading/trailing underscores are considered valid. Accepts one of the following values:
+
+- `forbid` - a leading/trailing underscore is not allowed at all.
+- `allow` - existence of a leading/trailing underscore is not explicitly enforced.
+- `require` - a leading/trailing underscore must be included.
+
+#### `prefix` / `suffix`
+
+The `prefix` / `suffix` options control which prefix/suffix strings must exist for the identifier. Accepts an array of strings.
+
+If these are provided, the identifier must start with one of the provided values. For example, if you provide `{ prefix: ['IFace', 'Class', 'Type'] }`, then the following names are valid: `IFaceFoo`, `ClassBar`, `TypeBaz`, but the name `Bang` is not valid, as it contains none of the prefixes.
+
+### Selector Options
+
+- `selector` (see "Allowed Selectors, Modifiers and Types" below).
+- `filter` accepts a regular expression (anything accepted into `new RegExp(filter)`). It allows you to limit the scope of this configuration to names that match this regex.
+- `modifiers` allows you to specify which modifiers to granularly apply to, such as the accessibility (`private`/`public`/`protected`), or if the thing is `static`, etc.
+  - The name must match _all_ of the modifiers.
+  - For example, if you provide `{ modifiers: ['private', 'static', 'readonly'] }`, then it will only match something that is `private static readonly`, and something that is just `private` will not match.
+- `types` allows you to specify which types to match. This option supports simple, primitive types only (`boolean`, `string`, `number`, `array`, `function`).
+  - The name must match _one_ of the types.
+  - **_NOTE - Using this option will require that you lint with type information._**
+  - For example, this lets you do things like enforce that `boolean` variables are prefixed with a verb.
+  - `boolean` matches any type assignable to `boolean | null | undefined`
+  - `string` matches any type assignable to `string | null | undefined`
+  - `number` matches any type assignable to `number | null | undefined`
+  - `array` matches any type assignable to `Array<unknown> | null | undefined`
+  - `function` matches any type assignable to `Function | null | undefined`
+
+The ordering of selectors does not matter. The implementation will automatically sort the selectors to ensure they match from most-specific to least specific. It will keep checking selectors in that order until it finds one that matches the name.
+
+For example, if you provide the following config:
+
+```ts
+[
+  /* 1 */ { selector: 'default', format: ['camelCase'] },
+  /* 2 */ { selector: 'variable', format: ['snake_case'] },
+  /* 3 */ { selector: 'variable', type: ['boolean'], format: ['UPPER_CASE'] },
+  /* 4 */ { selector: 'variableLike', format: ['PascalCase'] },
+];
+```
+
+Then for the code `const x = 1`, the rule will validate the selectors in the following order: `3`, `2`, `4`, `1`.
+
+#### Allowed Selectors, Modifiers and Types
+
+There are two types of selectors, individual selectors, and grouped selectors.
+
+##### Individual Selectors
+
+Individual Selectors match specific, well-defined sets. There is no overlap between each of the individual selectors.
+
+- `variable` - matches any `var` / `let` / `const` variable name.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: `boolean`, `string`, `number`, `function`, `array`.
+- `function` - matches any named function declaration or named function expression.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: none.
+- `parameter` - matches any function parameter. Does not match parameter properties.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: `boolean`, `string`, `number`, `function`, `array`.
+- `property` - matches any object, class, or object type property. Does not match properties that have direct function expression or arrow function expression values.
+  - Allowed `modifiers`: `private`, `protected`, `public`, `static`, `readonly`, `abstract`.
+  - Allowed `types`: `boolean`, `string`, `number`, `function`, `array`.
+- `parameterProperty` - matches any parameter property.
+  - Allowed `modifiers`: `private`, `protected`, `public`, `readonly`.
+  - Allowed `types`: `boolean`, `string`, `number`, `function`, `array`.
+- `method` - matches any object, class, or object type method. Also matches properties that have direct function expression or arrow function expression values. Does not match accessors.
+  - Allowed `modifiers`: `private`, `protected`, `public`, `static`, `readonly`, `abstract`.
+  - Allowed `types`: none.
+- `accessor` - matches any accessor.
+  - Allowed `modifiers`: `private`, `protected`, `public`, `static`, `readonly`, `abstract`.
+  - Allowed `types`: `boolean`, `string`, `number`, `function`, `array`.
+- `enumMember` - matches any enum member.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: none.
+- `class` - matches any class declaration.
+  - Allowed `modifiers`: `abstract`.
+  - Allowed `types`: none.
+- `interface` - matches any interface declaration.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: none.
+- `typeAlias` - matches any type alias declaration.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: none.
+- `enum` - matches any enum declaration.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: none.
+- `typeParameter` - matches any generic type parameter declaration.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: none.
+
+##### Group Selectors
+
+Group Selectors are provided for convenience, and essentially bundle up sets of individual selectors.
+
+- `default` - matches everything.
+  - Allowed `modifiers`: `private`, `protected`, `public`, `static`, `readonly`, `abstract`.
+  - Allowed `types`: none.
+- `variableLike` - matches the same as `variable`, `function` and `parameter`.
+  - Allowed `modifiers`: none.
+  - Allowed `types`: none.
+- `memberLike` - matches the same as `property`, `parameterProperty`, `method`, `accessor`, `enumMember`.
+  - Allowed `modifiers`: `private`, `protected`, `public`, `static`, `readonly`, `abstract`.
+  - Allowed `types`: none.
+- `typeLike` - matches the same as `class`, `interface`, `typeAlias`, `enum`, `typeParameter`.
+  - Allowed `modifiers`: `abstract`.
+  - Allowed `types`: none.
+
+## Examples
+
+### Enforce that all variables, functions and properties follow are camelCase
+
+```json
+{
+  "@typescript-eslint/naming-conventions": [
+    "error",
+    { "selector": "variableLike", "format": ["camelCase"] }
+  ]
+}
+```
+
+### Enforce that private members are prefixed with an underscore
+
+```json
+{
+  "@typescript-eslint/naming-conventions": [
+    "error",
+    {
+      "selector": "memberLike",
+      "modifier": ["private"],
+      "format": ["camelCase"],
+      "leadingUnderscore": "require"
+    }
+  ]
+}
+```
+
+### Enforce that boolean variables are prefixed with an allowed verb
+
+```json
+{
+  "@typescript-eslint/naming-conventions": [
+    "error",
+    {
+      "selector": "variable",
+      "types": ["boolean"],
+      "format": ["PascalCase"],
+      "prefix": ["is", "should", "has", "can", "did", "will"]
+    }
+  ]
+}
+```
+
+### Enforce that all variables are either in camelCase or UPPER_CASE
+
+```json
+{
+  "@typescript-eslint/naming-conventions": [
+    "error",
+    {
+      "selector": "variable",
+      "format": ["camelCase", "UPPER_CASE"]
+    }
+  ]
+}
+```
+
+### Enforce that type parameters (generics) are prefixed with `T`
+
+```json
+{
+  "@typescript-eslint/naming-conventions": [
+    "error",
+    {
+      "selector": "typeParameter",
+      "format": ["PascalCase"],
+      "prefix": ["T"]
+    }
+  ]
+}
+```
+
+### Enforce the codebase follows ESLint's `camelcase` conventions
+
+```json
+{
+  "@typescript-eslint/naming-conventions": [
+    "error",
+    {
+      "selector": "default",
+      "format": ["camelCase"]
+    },
+
+    {
+      "selector": "variable",
+      "format": ["camelCase", "UPPER_CASE"]
+    },
+    {
+      "selector": "parameter",
+      "format": ["camelCase"],
+      "leadingUnderscore": "allow"
+    },
+
+    {
+      "selector": "memberLike",
+      "modifiers": ["private"],
+      "format": ["camelCase"],
+      "leadingUnderscore": "require"
+    },
+
+    {
+      "selector": "typeLike",
+      "format": ["PascalCase"]
+    }
+  ]
+}
+```
+
+## When Not To Use It
+
+If you do not want to enforce naming conventions for anything.