Linter

Deno ships with a built in code linter for JavaScript and TypeScript.

Note: linter is a new feature and still unstable thus it requires --unstable flag

`

  1. # lint all JS/TS files in the current directory and subdirectoriesdeno lint --unstable# lint specific filesdeno lint --unstable myfile1.ts myfile2.ts# print result as JSONdeno lint --unstable --json# read from stdincat file.ts | deno lint --unstable -

`

For more detail, run deno lint --help.

Available rules

  • adjacent-overload-signatures
  • ban-ts-comment
  • ban-types
  • ban-untagged-ignore
  • camelcase
  • constructor-super
  • for-direction
  • getter-return
  • no-array-constructor
  • no-async-promise-executor
  • no-case-declarations
  • no-class-assign
  • no-compare-neg-zero
  • no-cond-assign
  • no-constant-condition
  • no-control-regex
  • no-debugger
  • no-delete-var
  • no-dupe-args
  • no-dupe-class-members
  • no-dupe-else-if
  • no-dupe-keys
  • no-duplicate-case
  • no-empty
  • no-empty-character-class
  • no-empty-interface
  • no-empty-pattern
  • no-ex-assign
  • no-explicit-any
  • no-extra-boolean-cast
  • no-extra-non-null-assertion
  • no-extra-semi
  • no-fallthrough
  • no-func-assign
  • no-global-assign
  • no-import-assign
  • no-inferrable-types
  • no-inner-declarations
  • no-invalid-regexp
  • no-irregular-whitespace
  • no-misused-new
  • no-mixed-spaces-and-tabs
  • no-namespace
  • no-new-symbol
  • no-obj-calls
  • no-octal
  • no-prototype-builtins
  • no-redeclare
  • no-regex-spaces
  • no-self-assign
  • no-setter-return
  • no-shadow-restricted-names
  • no-this-alias
  • no-this-before-super
  • no-undef
  • no-unreachable
  • no-unsafe-finally
  • no-unsafe-negation
  • no-unused-labels
  • no-with
  • prefer-as-const
  • prefer-const
  • prefer-namespace-keyword
  • require-await
  • require-yield
  • use-isnan
  • valid-typeof

For more detail about each rule, visit the deno_lint rule documentation.

Ignore directives

Files

To ignore whole file // deno-lint-ignore-file directive should placed at the top of the file:

`

  1. // deno-lint-ignore-file
  2. function foo(): any {  // ...}

`

Ignore directive must be placed before first statement or declaration:

`

  1. // Copyright 2020 the Deno authors. All rights reserved. MIT license./** * Some JS doc **/
  2. // deno-lint-ignore-file
  3. import { bar } from "./bar.js";
  4. function foo(): any {  // ...}

`

You can also ignore certain diagnostics in the whole file

`

  1. // deno-lint-ignore-file no-explicit-any no-empty
  2. function foo(): any {  // ...}

`

Diagnostics

To ignore certain diagnostic // deno-lint-ignore <codes...> directive should be placed before offending line. Specifying ignored rule name is required:

`

  1. // deno-lint-ignore no-explicit-anyfunction foo(): any {  // ...}
  2. // deno-lint-ignore no-explicit-any explicit-function-return-typefunction bar(a: any) {  // ...}

`