124 lines
4.0 KiB
JavaScript
124 lines
4.0 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const DescriptionFileUtils = require("./DescriptionFileUtils");
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const getInnerRequest = require("./getInnerRequest");
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/** @typedef {import("./Resolver")} Resolver */
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/** @typedef {import("./Resolver").JsonPrimitive} JsonPrimitive */
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/** @typedef {import("./Resolver").ResolveRequest} ResolveRequest */
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/** @typedef {import("./Resolver").ResolveStepHook} ResolveStepHook */
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// Sentinel stored in `_fieldDataCache` when a description file does not
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// contain a usable alias field object. Lets us distinguish "not cached yet"
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// from "no valid field" without calling back into `getField`.
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const NO_FIELD_OBJECT = Symbol("NoFieldObject");
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module.exports = class AliasFieldPlugin {
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/**
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* @param {string | ResolveStepHook} source source
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* @param {string | string[]} field field
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* @param {string | ResolveStepHook} target target
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*/
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constructor(source, field, target) {
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this.source = source;
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this.field = field;
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this.target = target;
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// `this.field` is fixed for the plugin's lifetime, so caching
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// per description-file content is safe. The cached value is either
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// the resolved alias-map object or the `NO_FIELD_OBJECT` sentinel
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// meaning "description file has no usable alias field".
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/** @type {WeakMap<import("./Resolver").JsonObject, { [k: string]: JsonPrimitive } | typeof NO_FIELD_OBJECT>} */
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this._fieldDataCache = new WeakMap();
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}
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/**
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* @param {Resolver} resolver the resolver
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* @returns {void}
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*/
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apply(resolver) {
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const target = resolver.ensureHook(this.target);
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resolver
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.getHook(this.source)
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.tapAsync("AliasFieldPlugin", (request, resolveContext, callback) => {
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if (!request.descriptionFileData) return callback();
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const innerRequest = getInnerRequest(resolver, request);
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if (!innerRequest) return callback();
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const { descriptionFileData } = request;
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let fieldData = this._fieldDataCache.get(descriptionFileData);
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if (fieldData === undefined) {
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const raw = DescriptionFileUtils.getField(
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descriptionFileData,
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this.field,
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);
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fieldData =
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raw === null || typeof raw !== "object"
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? NO_FIELD_OBJECT
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: /** @type {{ [k: string]: JsonPrimitive }} */ (raw);
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this._fieldDataCache.set(descriptionFileData, fieldData);
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}
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if (fieldData === NO_FIELD_OBJECT) {
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if (resolveContext.log) {
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resolveContext.log(
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`Field '${this.field}' doesn't contain a valid alias configuration`,
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);
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}
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return callback();
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}
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/** @type {JsonPrimitive | undefined} */
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const data = Object.prototype.hasOwnProperty.call(
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fieldData,
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innerRequest,
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)
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? /** @type {{ [Key in string]: JsonPrimitive }} */ (fieldData)[
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innerRequest
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]
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: innerRequest.startsWith("./")
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? /** @type {{ [Key in string]: JsonPrimitive }} */ (fieldData)[
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innerRequest.slice(2)
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]
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: undefined;
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if (data === innerRequest) return callback();
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if (data === undefined) return callback();
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if (data === false) {
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/** @type {ResolveRequest} */
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const ignoreObj = {
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...request,
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path: false,
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};
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if (typeof resolveContext.yield === "function") {
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resolveContext.yield(ignoreObj);
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return callback(null, null);
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}
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return callback(null, ignoreObj);
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}
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/** @type {ResolveRequest} */
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const obj = {
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...request,
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path: /** @type {string} */ (request.descriptionFileRoot),
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request: /** @type {string} */ (data),
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fullySpecified: false,
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};
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resolver.doResolve(
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target,
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obj,
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`aliased from description file ${
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request.descriptionFilePath
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} with mapping '${innerRequest}' to '${/** @type {string} */ data}'`,
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resolveContext,
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(err, result) => {
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if (err) return callback(err);
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// Don't allow other aliasing or raw request
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if (result === undefined) return callback(null, null);
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callback(null, result);
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},
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);
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});
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}
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};
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