namespace.md

namespace

Enforces names exist at the time they are dereferenced, when imported as a full namespace (i.e. import * as foo from './foo'; foo.bar(); will report if bar is not exported by ./foo.).

Will report at the import declaration if there are no exported names found.

Also, will report for computed references (i.e. foo["bar"]()).

Reports on assignment to a member of an imported namespace.

Note: for modules, the plugin will find exported names from jsnext:main, if present in package.json. Redux's npm module includes this key, and thereby is lintable, for example. Otherwise, the whole node_modules folder is ignored by default (import/ignore) as most published modules are formatted in CommonJS, which at time of this writing is not able to be analyzed for exports.

Rule Details

Currently, this rule does not check for possible redefinition of the namespace in an intermediate scope. Adherence to the ESLint no-shadow rule for namespaces will prevent this from being a problem.

For ES7, reports if an exported namespace would be empty (no names exported from the referenced module.)

Given:

// @module ./named-exports
export const a = 1
const b = 2
export { b }

const c = 3
export { c as d }

export class ExportedClass { }

// ES7
export * as deep from './deep'

and:

// @module ./deep
export const e = "MC2"

See what is valid and reported:

// @module ./foo
import * as names from './named-exports'

function great() {
  return names.a + names.b  // so great https://youtu.be/ei7mb8UxEl8
}

function notGreat() {
  doSomethingWith(names.c) // Reported: 'c' not found in imported namespace 'names'.

  const { a, b, c } = names // also reported, only for 'c'
}

// also tunnels through re-exported namespaces!
function deepTrouble() {
  doSomethingWith(names.deep.e) // fine
  doSomethingWith(names.deep.f) // Reported: 'f' not found in deeply imported namespace 'names.deep'.
}

Further Reading

• Lee Byron's ES7 export proposal
• import/ignore setting
• jsnext:main