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no-namespace

Disallow TypeScript namespaces.

✅

Extending "plugin:@typescript-eslint/recommended" in an ESLint configuration enables this rule.

TypeScript historically allowed a form of code organization called "custom modules" (module Example {}), later renamed to "namespaces" (namespace Example). Namespaces are an outdated way to organize TypeScript code. ES2015 module syntax is now preferred (import/export).

This rule does not report on the use of TypeScript module declarations to describe external APIs (declare module 'foo' {}).

.eslintrc.cjs
module.exports = {
  "rules": {
    "@typescript-eslint/no-namespace": "error"
  }
};
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Examples​

Examples of code with the default options:

module foo {}
namespace foo {}

declare module foo {}
declare namespace foo {}
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Options​

This rule accepts the following options

type Options = [
  {
    /** Whether to allow `declare` with custom TypeScript namespaces. */
    allowDeclarations?: boolean;
    /** Whether to allow `declare` with custom TypeScript namespaces inside definition files. */
    allowDefinitionFiles?: boolean;
  },
];

const defaultOptions: Options = [
  { allowDeclarations: false, allowDefinitionFiles: true },
];

allowDeclarations​

Examples of code with the { "allowDeclarations": true } option:

module foo {}
namespace foo {}
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Examples of code for the { "allowDeclarations": false } option:

module foo {}
namespace foo {}
declare module foo {}
declare namespace foo {}
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allowDefinitionFiles​

Examples of code for the { "allowDefinitionFiles": true } option:

// if outside a d.ts file
module foo {}
namespace foo {}

// if outside a d.ts file and allowDeclarations = false
module foo {}
namespace foo {}
declare module foo {}
declare namespace foo {}
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When Not To Use It​

If you are using the ES2015 module syntax, then you will not need this rule.

Further Reading​

Resources​