typescript/no-explicit-any Restriction

🛠️ An auto-fix is available for this rule for some violations.

What it does

Disallows explicit use of the any type.

Why is this bad?

The any type in TypeScript is a dangerous "escape hatch" from the type system. Using any disables many type checking rules and is generally best used only as a last resort or when prototyping code. This rule reports on explicit uses of the any keyword as a type annotation.

TypeScript's --noImplicitAny compiler option prevents an implied any, but doesn't prevent any from being explicitly used the way this rule does.

Example

Examples of incorrect code for this rule:

const age: any = "seventeen";
const ages: any[] = ["seventeen"];
const ages: Array<any> = ["seventeen"];
function greet(): any {}
function greet(): any[] {}
function greet(): Array<any> {}
function greet(): Array<Array<any>> {}
function greet(param: Array<any>): string {}
function greet(param: Array<any>): Array<any> {}

Examples of correct code for this rule:

const age: number = 17;
const ages: number[] = [17];
const ages: Array<number> = [17];
function greet(): string {}
function greet(): string[] {}
function greet(): Array<string> {}
function greet(): Array<Array<string>> {}
function greet(param: Array<string>): string {}
function greet(param: Array<string>): Array<string> {}

Options

This rule accepts the following options:

ignoreRestArgs

A boolean to specify if arrays from the rest operator are considered ok. false by default.

fixToUnknown

Whether to enable auto-fixing in which the any type is converted to the unknown type. false by default.

How to use

To enable this rule in the CLI or using the config file, you can use:

CLI

oxlint --deny typescript/no-explicit-any

Config (.oxlintrc.json)

{
  "rules": {
    "typescript/no-explicit-any": "error"
  }
}

References

• Rule Source