NPM.Resolution.Exports (NPM v0.6.0)

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Parse and resolve the exports field from package.json.

Modern npm packages use the exports field (a.k.a. "export map") to define entry points and restrict access to internal modules.

Supports:

  • String shorthand: "exports": "./index.js"
  • Subpath exports: "exports": { ".": "./index.js", "./utils": "./lib/utils.js" }
  • Conditional exports: "exports": { "import": "./esm.js", "require": "./cjs.js" }
  • Nested conditions: "exports": { ".": { "import": "./esm.js", "default": "./cjs.js" } }

Summary

Types

export_map()

Functions

conditions(export_map)

Extracts all conditions used in the export map.

exported?(subpath, export_map)

Checks if a subpath is exported by the export map.

module_type(arg1)

Detect whether a package uses ESM (type: "module") or CJS.

parse(arg1)

Parse the exports field from a package.json map.

resolve(export_map, subpath, conditions \\ ["default"])

Resolve an import path against an export map.

subpaths(export_map)

List all exported subpaths from an export map.

validate(export_map, base_dir)

Validates that all export paths resolve to existing files.

Types

export_map()

@type export_map() ::
  String.t() | [export_map()] | %{required(String.t()) => export_map()} | nil

Functions

conditions(export_map)

@spec conditions(map() | nil) :: [String.t()]

Extracts all conditions used in the export map.

exported?(subpath, export_map)

@spec exported?(String.t(), map() | nil) :: boolean()

Checks if a subpath is exported by the export map.

module_type(arg1)

@spec module_type(map()) :: :esm | :cjs

Detect whether a package uses ESM (type: "module") or CJS.

parse(arg1)

@spec parse(map()) :: %{required(String.t()) => String.t() | map()} | nil

Parse the exports field from a package.json map.

Returns a normalized map of subpath → target mappings, or nil if no exports field.

resolve(export_map, subpath, conditions \\ ["default"])

@spec resolve(map(), String.t(), [String.t()]) :: {:ok, String.t()} | :error

Resolve an import path against an export map.

Given a subpath (e.g. ".", "./utils") and a list of conditions (e.g. ["import", "default"]), returns the resolved file path.

subpaths(export_map)

@spec subpaths(map()) :: [String.t()]

List all exported subpaths from an export map.

validate(export_map, base_dir)

@spec validate(map() | nil, String.t()) ::
  {:ok, [String.t()]} | {:error, [String.t()]}

Validates that all export paths resolve to existing files.