eslint/lib/init/config-file.js

   1 /**
   2  * @fileoverview Helper to locate and load configuration files.
   3  * @author Nicholas C. Zakas
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Requirements
  10 //------------------------------------------------------------------------------
  11
  12 const fs = require("fs"),
  13     path = require("path"),
  14     stringify = require("json-stable-stringify-without-jsonify");
  15
  16 const debug = require("debug")("eslint:config-file");
  17
  18 //------------------------------------------------------------------------------
  19 // Helpers
  20 //------------------------------------------------------------------------------
  21
  22 /**
  23  * Determines sort order for object keys for json-stable-stringify
  24  *
  25  * see: https://github.com/samn/json-stable-stringify#cmp
  26  * @param   {Object} a The first comparison object ({key: akey, value: avalue})
  27  * @param   {Object} b The second comparison object ({key: bkey, value: bvalue})
  28  * @returns {number}   1 or -1, used in stringify cmp method
  29  */
  30 function sortByKey(a, b) {
  31     return a.key > b.key ? 1 : -1;
  32 }
  33
  34 //------------------------------------------------------------------------------
  35 // Private
  36 //------------------------------------------------------------------------------
  37
  38 /**
  39  * Writes a configuration file in JSON format.
  40  * @param {Object} config The configuration object to write.
  41  * @param {string} filePath The filename to write to.
  42  * @returns {void}
  43  * @private
  44  */
  45 function writeJSONConfigFile(config, filePath) {
  46     debug(`Writing JSON config file: ${filePath}`);
  47
  48     const content = `${stringify(config, { cmp: sortByKey, space: 4 })}\n`;
  49
  50     fs.writeFileSync(filePath, content, "utf8");
  51 }
  52
  53 /**
  54  * Writes a configuration file in YAML format.
  55  * @param {Object} config The configuration object to write.
  56  * @param {string} filePath The filename to write to.
  57  * @returns {void}
  58  * @private
  59  */
  60 function writeYAMLConfigFile(config, filePath) {
  61     debug(`Writing YAML config file: ${filePath}`);
  62
  63     // lazy load YAML to improve performance when not used
  64     const yaml = require("js-yaml");
  65
  66     const content = yaml.safeDump(config, { sortKeys: true });
  67
  68     fs.writeFileSync(filePath, content, "utf8");
  69 }
  70
  71 /**
  72  * Writes a configuration file in JavaScript format.
  73  * @param {Object} config The configuration object to write.
  74  * @param {string} filePath The filename to write to.
  75  * @throws {Error} If an error occurs linting the config file contents.
  76  * @returns {void}
  77  * @private
  78  */
  79 function writeJSConfigFile(config, filePath) {
  80     debug(`Writing JS config file: ${filePath}`);
  81
  82     let contentToWrite;
  83     const stringifiedContent = `module.exports = ${stringify(config, { cmp: sortByKey, space: 4 })};\n`;
  84
  85     try {
  86         const { CLIEngine } = require("../cli-engine");
  87         const linter = new CLIEngine({
  88             baseConfig: config,
  89             fix: true,
  90             useEslintrc: false
  91         });
  92         const report = linter.executeOnText(stringifiedContent);
  93
  94         contentToWrite = report.results[0].output || stringifiedContent;
  95     } catch (e) {
  96         debug("Error linting JavaScript config file, writing unlinted version");
  97         const errorMessage = e.message;
  98
  99         contentToWrite = stringifiedContent;
 100         e.message = "An error occurred while generating your JavaScript config file. ";
 101         e.message += "A config file was still generated, but the config file itself may not follow your linting rules.";
 102         e.message += `\nError: ${errorMessage}`;
 103         throw e;
 104     } finally {
 105         fs.writeFileSync(filePath, contentToWrite, "utf8");
 106     }
 107 }
 108
 109 /**
 110  * Writes a configuration file.
 111  * @param {Object} config The configuration object to write.
 112  * @param {string} filePath The filename to write to.
 113  * @returns {void}
 114  * @throws {Error} When an unknown file type is specified.
 115  * @private
 116  */
 117 function write(config, filePath) {
 118     switch (path.extname(filePath)) {
 119         case ".js":
 120         case ".cjs":
 121             writeJSConfigFile(config, filePath);
 122             break;
 123
 124         case ".json":
 125             writeJSONConfigFile(config, filePath);
 126             break;
 127
 128         case ".yaml":
 129         case ".yml":
 130             writeYAMLConfigFile(config, filePath);
 131             break;
 132
 133         default:
 134             throw new Error("Can't write to unknown file type.");
 135     }
 136 }
 137
 138 //------------------------------------------------------------------------------
 139 // Public Interface
 140 //------------------------------------------------------------------------------
 141
 142 module.exports = {
 143     write
 144 };