ESLint Plugin TypeScript
## Installation
Make sure you have TypeScript and @typescript-eslint/parser installed, then install the plugin:
```sh
npm i @typescript-eslint/eslint-plugin --save-dev
```
It is important that you use the same version number for `@typescript-eslint/parser` and `@typescript-eslint/eslint-plugin`.
**Note:** If you installed ESLint globally (using the `-g` flag) then you must also install `@typescript-eslint/eslint-plugin` globally.
## Usage
Add `@typescript-eslint/parser` to the `parser` field and `@typescript-eslint` to the plugins section of your `.eslintrc` configuration file:
```json
{
"parser": "@typescript-eslint/parser",
"plugins": ["@typescript-eslint"]
}
```
Then configure the rules you want to use under the rules section.
```json
{
"parser": "@typescript-eslint/parser",
"plugins": ["@typescript-eslint"],
"rules": {
"@typescript-eslint/rule-name": "error"
}
}
```
You can also enable all the recommended rules at once. Add `plugin:@typescript-eslint/recommended` in extends:
```json
{
"extends": ["plugin:@typescript-eslint/recommended"]
}
```
If you want to use rules which require type information, you will need to specify a path to your tsconfig.json file in the "project" property of "parserOptions".
```json
{
"parser": "@typescript-eslint/parser",
"parserOptions": {
"project": "./tsconfig.json"
},
"plugins": ["@typescript-eslint"],
"rules": {
"@typescript-eslint/restrict-plus-operands": "error"
}
}
```
See [@typescript-eslint/parser's README.md](../parser/README.md) for more information on the available "parserOptions".
## Usage with Prettier
Install [`eslint-config-prettier`](https://github.com/prettier/eslint-config-prettier) to disable our code formatting related rules:
```json
{
"extends": [
"plugin:@typescript-eslint/recommended",
"prettier",
"prettier/@typescript-eslint"
]
}
```
**Note: Make sure you have `eslint-config-prettier@4.0.0` or newer.**
## Usage with Airbnb
Airbnb has two configs, a base one [`eslint-config-airbnb-base`](https://github.com/airbnb/javascript/tree/master/packages/eslint-config-airbnb-base) and one that includes rules for React [`eslint-config-airbnb`](https://github.com/airbnb/javascript/tree/master/packages/eslint-config-airbnb).
First you'll need to install the config according to the instructions in one of the links above. `npx install-peerdeps --dev eslint-config-airbnb` or `npx install-peerdeps --dev eslint-config-airbnb-base` should work if you are using **npm 5+**.
Then you should add `airbnb` (or `airbnb-base`) to your `extends` section of `.eslintrc`. You might also want to turn on `plugin:@typescript-eslint/recommended` as well to enable all of the recommended rules.
```json
{
"extends": ["airbnb-base", "plugin:@typescript-eslint/recommended"]
}
```
**Note: You can use Airbnb's rules alongside Prettier, see [Usage with Prettier](#usage-with-prettier)**
## Supported Rules
**Key**: :heavy_check_mark: = recommended, :wrench: = fixable, :thought_balloon: = requires type information
| Name | Description | :heavy_check_mark: | :wrench: | :thought_balloon: |
| --------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------ | -------- | ----------------- |
| [`@typescript-eslint/adjacent-overload-signatures`](./docs/rules/adjacent-overload-signatures.md) | Require that member overloads be consecutive (`adjacent-overload-signatures` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/array-type`](./docs/rules/array-type.md) | Requires using either `T[]` or `Array` for arrays (`array-type` from TSLint) | :heavy_check_mark: | :wrench: | |
| [`@typescript-eslint/ban-types`](./docs/rules/ban-types.md) | Enforces that types will not to be used (`ban-types` from TSLint) | :heavy_check_mark: | :wrench: | |
| [`@typescript-eslint/ban-ts-ignore`](./docs/rules/ban-ts-ignore.md) | Bans “// @ts-ignore” comments from being used (`ban-ts-ignore` from TSLint) | | | |
| [`@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 (`class-name` from TSLint) | :heavy_check_mark: | | |
| [`@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 (`member-access` from TSLint) | :heavy_check_mark: | | |
| [`@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 (`indent` from TSLint) | :heavy_check_mark: | :wrench: | |
| [`@typescript-eslint/interface-name-prefix`](./docs/rules/interface-name-prefix.md) | Require that interface names be prefixed with `I` (`interface-name` from TSLint) | :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 (`member-ordering` from TSLint) | | | |
| [`@typescript-eslint/no-angle-bracket-type-assertion`](./docs/rules/no-angle-bracket-type-assertion.md) | Enforces the use of `as Type` assertions instead of `` assertions (`no-angle-bracket-type-assertion` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-array-constructor`](./docs/rules/no-array-constructor.md) | Disallow generic `Array` constructors | :heavy_check_mark: | :wrench: | |
| [`@typescript-eslint/no-empty-interface`](./docs/rules/no-empty-interface.md) | Disallow the declaration of empty interfaces (`no-empty-interface` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-explicit-any`](./docs/rules/no-explicit-any.md) | Disallow usage of the `any` type (`no-any` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-extraneous-class`](./docs/rules/no-extraneous-class.md) | Forbids the use of classes as namespaces (`no-unnecessary-class` from TSLint) | | | |
| [`@typescript-eslint/no-for-in-array`](./docs/rules/no-for-in-array.md) | Disallow iterating over an array with a for-in loop (`no-for-in-array` from TSLint) | | | :thought_balloon: |
| [`@typescript-eslint/no-inferrable-types`](./docs/rules/no-inferrable-types.md) | Disallows explicit type declarations for variables or parameters initialized to a number, string, or boolean. (`no-inferrable-types` from TSLint) | :heavy_check_mark: | :wrench: | |
| [`@typescript-eslint/no-misused-new`](./docs/rules/no-misused-new.md) | Enforce valid definition of `new` and `constructor`. (`no-misused-new` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-namespace`](./docs/rules/no-namespace.md) | Disallow the use of custom TypeScript modules and namespaces (`no-namespace` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-non-null-assertion`](./docs/rules/no-non-null-assertion.md) | Disallows non-null assertions using the `!` postfix operator (`no-non-null-assertion` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-object-literal-type-assertion`](./docs/rules/no-object-literal-type-assertion.md) | Forbids an object literal to appear in a type assertion expression (`no-object-literal-type-assertion` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-parameter-properties`](./docs/rules/no-parameter-properties.md) | Disallow the use of parameter properties in class constructors. (`no-parameter-properties` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-require-imports`](./docs/rules/no-require-imports.md) | Disallows invocation of `require()` (`no-require-imports` from TSLint) | | | |
| [`@typescript-eslint/no-this-alias`](./docs/rules/no-this-alias.md) | Disallow aliasing `this` (`no-this-assignment` from TSLint) | | | |
| [`@typescript-eslint/no-triple-slash-reference`](./docs/rules/no-triple-slash-reference.md) | Disallow `/// ` comments (`no-reference` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-type-alias`](./docs/rules/no-type-alias.md) | Disallow the use of type aliases (`interface-over-type-literal` from TSLint) | | | |
| [`@typescript-eslint/no-unnecessary-qualifier`](./docs/rules/no-unnecessary-qualifier.md) | Warns when a namespace qualifier is unnecessary (`no-unnecessary-qualifier` from TSLint) | | :wrench: | :thought_balloon: |
| [`@typescript-eslint/no-unnecessary-type-assertion`](./docs/rules/no-unnecessary-type-assertion.md) | Warns if a type assertion does not change the type of an expression (`no-unnecessary-type-assertion` from TSLint) | | :wrench: | :thought_balloon: |
| [`@typescript-eslint/no-unused-vars`](./docs/rules/no-unused-vars.md) | Disallow unused variables (`no-unused-variable` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/no-use-before-define`](./docs/rules/no-use-before-define.md) | Disallow the use of variables before they are defined | :heavy_check_mark: | | |
| [`@typescript-eslint/no-useless-constructor`](./docs/rules/no-useless-constructor.md) | Disallow unnecessary constructors | | | |
| [`@typescript-eslint/no-var-requires`](./docs/rules/no-var-requires.md) | Disallows the use of require statements except in import statements (`no-var-requires` from TSLint) | :heavy_check_mark: | | |
| [`@typescript-eslint/prefer-function-type`](./docs/rules/prefer-function-type.md) | Use function types instead of interfaces with call signatures (`callable-types` from TSLint) | | :wrench: | |
| [`@typescript-eslint/prefer-interface`](./docs/rules/prefer-interface.md) | Prefer an interface declaration over a type literal (type T = { ... }) (`interface-over-type-literal` from TSLint) | :heavy_check_mark: | :wrench: | |
| [`@typescript-eslint/prefer-namespace-keyword`](./docs/rules/prefer-namespace-keyword.md) | Require the use of the `namespace` keyword instead of the `module` keyword to declare custom TypeScript modules. (`no-internal-module` from TSLint) | :heavy_check_mark: | :wrench: | |
| [`@typescript-eslint/promise-function-async`](./docs/rules/promise-function-async.md) | Requires any function or method that returns a Promise to be marked async. (`promise-function-async` from TSLint) | | | :thought_balloon: |
| [`@typescript-eslint/restrict-plus-operands`](./docs/rules/restrict-plus-operands.md) | When adding two variables, operands must both be of type number or of type string. (`restrict-plus-operands` from TSLint) | | | :thought_balloon: |
| [`@typescript-eslint/type-annotation-spacing`](./docs/rules/type-annotation-spacing.md) | Require consistent spacing around type annotations (`typedef-whitespace` from TSLint) | :heavy_check_mark: | :wrench: | |
| [`@typescript-eslint/unified-signatures`](./docs/rules/unified-signatures.md) | Warns for any two overloads that could be unified into one. (`unified-signatures` from TSLint) | | | |