ExportsFieldPlugin.js 6.0 KB

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  1. /*
  2. MIT License http://www.opensource.org/licenses/mit-license.php
  3. Author Ivan Kopeykin @vankop
  4. */
  5. "use strict";
  6. const DescriptionFileUtils = require("./DescriptionFileUtils");
  7. const forEachBail = require("./forEachBail");
  8. const { processExportsField } = require("./util/entrypoints");
  9. const { parseIdentifier } = require("./util/identifier");
  10. const {
  11. invalidSegmentRegEx,
  12. deprecatedInvalidSegmentRegEx,
  13. } = require("./util/path");
  14. /** @typedef {import("./Resolver")} Resolver */
  15. /** @typedef {import("./Resolver").JsonObject} JsonObject */
  16. /** @typedef {import("./Resolver").ResolveRequest} ResolveRequest */
  17. /** @typedef {import("./Resolver").ResolveStepHook} ResolveStepHook */
  18. /** @typedef {import("./util/entrypoints").ExportsField} ExportsField */
  19. /** @typedef {import("./util/entrypoints").FieldProcessor} FieldProcessor */
  20. module.exports = class ExportsFieldPlugin {
  21. /**
  22. * @param {string | ResolveStepHook} source source
  23. * @param {Set<string>} conditionNames condition names
  24. * @param {string | string[]} fieldNamePath name path
  25. * @param {string | ResolveStepHook} target target
  26. */
  27. constructor(source, conditionNames, fieldNamePath, target) {
  28. this.source = source;
  29. this.target = target;
  30. this.conditionNames = conditionNames;
  31. this.fieldName = fieldNamePath;
  32. /** @type {WeakMap<JsonObject, FieldProcessor>} */
  33. this.fieldProcessorCache = new WeakMap();
  34. }
  35. /**
  36. * @param {Resolver} resolver the resolver
  37. * @returns {void}
  38. */
  39. apply(resolver) {
  40. const target = resolver.ensureHook(this.target);
  41. resolver
  42. .getHook(this.source)
  43. .tapAsync("ExportsFieldPlugin", (request, resolveContext, callback) => {
  44. // When there is no description file, abort
  45. if (!request.descriptionFilePath) return callback();
  46. if (
  47. // When the description file is inherited from parent, abort
  48. // (There is no description file inside of this package)
  49. request.relativePath !== "." ||
  50. request.request === undefined
  51. ) {
  52. return callback();
  53. }
  54. const remainingRequest =
  55. request.query || request.fragment
  56. ? (request.request === "." ? "./" : request.request) +
  57. request.query +
  58. request.fragment
  59. : request.request;
  60. const exportsField =
  61. /** @type {ExportsField|null|undefined} */
  62. (
  63. DescriptionFileUtils.getField(
  64. /** @type {JsonObject} */ (request.descriptionFileData),
  65. this.fieldName,
  66. )
  67. );
  68. if (!exportsField) return callback();
  69. if (request.directory) {
  70. return callback(
  71. new Error(
  72. `Resolving to directories is not possible with the exports field (request was ${remainingRequest}/)`,
  73. ),
  74. );
  75. }
  76. /** @type {string[]} */
  77. let paths;
  78. /** @type {string | null} */
  79. let usedField;
  80. try {
  81. // We attach the cache to the description file instead of the exportsField value
  82. // because we use a WeakMap and the exportsField could be a string too.
  83. // Description file is always an object when exports field can be accessed.
  84. let fieldProcessor = this.fieldProcessorCache.get(
  85. /** @type {JsonObject} */ (request.descriptionFileData),
  86. );
  87. if (fieldProcessor === undefined) {
  88. fieldProcessor = processExportsField(exportsField);
  89. this.fieldProcessorCache.set(
  90. /** @type {JsonObject} */ (request.descriptionFileData),
  91. fieldProcessor,
  92. );
  93. }
  94. [paths, usedField] = fieldProcessor(
  95. remainingRequest,
  96. this.conditionNames,
  97. );
  98. } catch (/** @type {unknown} */ err) {
  99. if (resolveContext.log) {
  100. resolveContext.log(
  101. `Exports field in ${request.descriptionFilePath} can't be processed: ${err}`,
  102. );
  103. }
  104. return callback(/** @type {Error} */ (err));
  105. }
  106. if (paths.length === 0) {
  107. return callback(
  108. new Error(
  109. `Package path ${remainingRequest} is not exported from package ${request.descriptionFileRoot} (see exports field in ${request.descriptionFilePath})`,
  110. ),
  111. );
  112. }
  113. forEachBail(
  114. paths,
  115. /**
  116. * @param {string} path path
  117. * @param {(err?: null|Error, result?: null|ResolveRequest) => void} callback callback
  118. * @param {number} i index
  119. * @returns {void}
  120. */
  121. (path, callback, i) => {
  122. const parsedIdentifier = parseIdentifier(path);
  123. if (!parsedIdentifier) return callback();
  124. const [relativePath, query, fragment] = parsedIdentifier;
  125. if (relativePath.length === 0 || !relativePath.startsWith("./")) {
  126. if (paths.length === i) {
  127. return callback(
  128. new Error(
  129. `Invalid "exports" target "${path}" defined for "${usedField}" in the package config ${request.descriptionFilePath}, targets must start with "./"`,
  130. ),
  131. );
  132. }
  133. return callback();
  134. }
  135. if (
  136. invalidSegmentRegEx.exec(relativePath.slice(2)) !== null &&
  137. deprecatedInvalidSegmentRegEx.test(relativePath.slice(2)) !== null
  138. ) {
  139. if (paths.length === i) {
  140. return callback(
  141. new Error(
  142. `Invalid "exports" target "${path}" defined for "${usedField}" in the package config ${request.descriptionFilePath}, targets must start with "./"`,
  143. ),
  144. );
  145. }
  146. return callback();
  147. }
  148. /** @type {ResolveRequest} */
  149. const obj = {
  150. ...request,
  151. request: undefined,
  152. path: resolver.join(
  153. /** @type {string} */ (request.descriptionFileRoot),
  154. relativePath,
  155. ),
  156. relativePath,
  157. query,
  158. fragment,
  159. };
  160. resolver.doResolve(
  161. target,
  162. obj,
  163. `using exports field: ${path}`,
  164. resolveContext,
  165. (err, result) => {
  166. if (err) return callback(err);
  167. // Don't allow to continue - https://github.com/webpack/enhanced-resolve/issues/400
  168. if (result === undefined) return callback(null, null);
  169. callback(null, result);
  170. },
  171. );
  172. },
  173. /**
  174. * @param {(null | Error)=} err error
  175. * @param {(null | ResolveRequest)=} result result
  176. * @returns {void}
  177. */
  178. (err, result) => callback(err, result || null),
  179. );
  180. });
  181. }
  182. };