76 lines
2.1 KiB
JavaScript
76 lines
2.1 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Natsu @xiaoxiaojx
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*/
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"use strict";
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const stripJsonComments = require("./strip-json-comments");
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/** @typedef {import("../Resolver").FileSystem} FileSystem */
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/** @typedef {import("../Resolver").JsonObject} JsonObject */
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/**
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* @typedef {object} ReadJsonOptions
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* @property {boolean=} stripComments Whether to strip JSONC comments
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*/
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/** @type {WeakMap<Buffer, JsonObject>} */
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const _stripCommentsCache = new WeakMap();
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/**
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* Read and parse JSON file (supports JSONC with comments).
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* Callback-based so a synchronous `fileSystem` stays synchronous all the
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* way through — Promise wrapping would defer resolution by a Promise tick
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* and break `resolveSync` when `tsconfig` is used together with
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* `useSyncFileSystemCalls: true`.
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* @param {FileSystem} fileSystem the file system
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* @param {string} jsonFilePath absolute path to JSON file
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* @param {ReadJsonOptions} options Options
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* @param {(err: NodeJS.ErrnoException | Error | null, content?: JsonObject) => void} callback callback
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* @returns {void}
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*/
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function readJson(fileSystem, jsonFilePath, options, callback) {
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const { stripComments = false } = options;
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const { readJson: fsReadJson } = fileSystem;
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if (fsReadJson && !stripComments) {
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fsReadJson(jsonFilePath, (err, content) => {
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if (err) return callback(err);
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callback(null, /** @type {JsonObject} */ (content));
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});
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return;
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}
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fileSystem.readFile(jsonFilePath, (err, data) => {
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if (err) return callback(err);
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const buf = /** @type {Buffer} */ (data);
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if (stripComments) {
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const cached = _stripCommentsCache.get(buf);
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if (cached !== undefined) return callback(null, cached);
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}
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let result;
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try {
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const jsonText = buf.toString();
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const jsonWithoutComments = stripComments
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? stripJsonComments(jsonText, {
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trailingCommas: true,
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whitespace: true,
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})
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: jsonText;
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result = JSON.parse(jsonWithoutComments);
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} catch (parseErr) {
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return callback(/** @type {Error} */ (parseErr));
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}
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if (stripComments) {
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_stripCommentsCache.set(buf, result);
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}
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callback(null, result);
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});
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}
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module.exports.readJson = readJson;
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