eslint/bin/eslint.js

   1 #!/usr/bin/env node
   2
   3 /**
   4  * @fileoverview Main CLI that is run via the eslint command.
   5  * @author Nicholas C. Zakas
   6  */
   7
   8 /* eslint no-console:off -- CLI */
   9
  10 "use strict";
  11
  12 // must do this initialization *before* other requires in order to work
  13 if (process.argv.includes("--debug")) {
  14     require("debug").enable("eslint:*,-eslint:code-path,eslintrc:*");
  15 }
  16
  17 //------------------------------------------------------------------------------
  18 // Helpers
  19 //------------------------------------------------------------------------------
  20
  21 /**
  22  * Read data from stdin til the end.
  23  *
  24  * Note: See
  25  * - https://github.com/nodejs/node/blob/master/doc/api/process.md#processstdin
  26  * - https://github.com/nodejs/node/blob/master/doc/api/process.md#a-note-on-process-io
  27  * - https://lists.gnu.org/archive/html/bug-gnu-emacs/2016-01/msg00419.html
  28  * - https://github.com/nodejs/node/issues/7439 (historical)
  29  *
  30  * On Windows using `fs.readFileSync(STDIN_FILE_DESCRIPTOR, "utf8")` seems
  31  * to read 4096 bytes before blocking and never drains to read further data.
  32  *
  33  * The investigation on the Emacs thread indicates:
  34  *
  35  * > Emacs on MS-Windows uses pipes to communicate with subprocesses; a
  36  * > pipe on Windows has a 4K buffer. So as soon as Emacs writes more than
  37  * > 4096 bytes to the pipe, the pipe becomes full, and Emacs then waits for
  38  * > the subprocess to read its end of the pipe, at which time Emacs will
  39  * > write the rest of the stuff.
  40  * @returns {Promise<string>} The read text.
  41  */
  42 function readStdin() {
  43     return new Promise((resolve, reject) => {
  44         let content = "";
  45         let chunk = "";
  46
  47         process.stdin
  48             .setEncoding("utf8")
  49             .on("readable", () => {
  50                 while ((chunk = process.stdin.read()) !== null) {
  51                     content += chunk;
  52                 }
  53             })
  54             .on("end", () => resolve(content))
  55             .on("error", reject);
  56     });
  57 }
  58
  59 /**
  60  * Get the error message of a given value.
  61  * @param {any} error The value to get.
  62  * @returns {string} The error message.
  63  */
  64 function getErrorMessage(error) {
  65
  66     // Lazy loading because this is used only if an error happened.
  67     const util = require("util");
  68
  69     // Foolproof -- third-party module might throw non-object.
  70     if (typeof error !== "object" || error === null) {
  71         return String(error);
  72     }
  73
  74     // Use templates if `error.messageTemplate` is present.
  75     if (typeof error.messageTemplate === "string") {
  76         try {
  77             const template = require(`../messages/${error.messageTemplate}.js`);
  78
  79             return template(error.messageData || {});
  80         } catch {
  81
  82             // Ignore template error then fallback to use `error.stack`.
  83         }
  84     }
  85
  86     // Use the stacktrace if it's an error object.
  87     if (typeof error.stack === "string") {
  88         return error.stack;
  89     }
  90
  91     // Otherwise, dump the object.
  92     return util.format("%o", error);
  93 }
  94
  95 /**
  96  * Catch and report unexpected error.
  97  * @param {any} error The thrown error object.
  98  * @returns {void}
  99  */
 100 function onFatalError(error) {
 101     process.exitCode = 2;
 102
 103     const { version } = require("../package.json");
 104     const message = getErrorMessage(error);
 105
 106     console.error(`
 107 Oops! Something went wrong! :(
 108
 109 ESLint: ${version}
 110
 111 ${message}`);
 112 }
 113
 114 //------------------------------------------------------------------------------
 115 // Execution
 116 //------------------------------------------------------------------------------
 117
 118 (async function main() {
 119     process.on("uncaughtException", onFatalError);
 120     process.on("unhandledRejection", onFatalError);
 121
 122     // Call the config initializer if `--init` is present.
 123     if (process.argv.includes("--init")) {
 124
 125         // `eslint --init` has been moved to `@eslint/create-config`
 126         console.warn("You can also run this command directly using 'npm init @eslint/config'.");
 127
 128         const spawn = require("cross-spawn");
 129
 130         spawn.sync("npm", ["init", "@eslint/config"], { encoding: "utf8", stdio: "inherit" });
 131         return;
 132     }
 133
 134     // Otherwise, call the CLI.
 135     process.exitCode = await require("../lib/cli").execute(
 136         process.argv,
 137         process.argv.includes("--stdin") ? await readStdin() : null,
 138         true
 139     );
 140 }()).catch(onFatalError);