feat: add patched Console transport for winston to make it work in the browser

src/logger/console.js

@@ -0,0 +1,123 @@
+/* eslint-disable */
+/*
+ * console.js: Transport for outputting to the console.
+ *
+ * (C) 2010 Charlie Robbins
+ * MIT LICENCE
+ */
+
+const os = require('os');
+// eslint-disable-next-line import/no-extraneous-dependencies
+const { LEVEL, MESSAGE } = require('triple-beam');
+// eslint-disable-next-line import/no-extraneous-dependencies
+const TransportStream = require('winston-transport');
+
+/**
+ * Transport for outputting to the console.
+ * @type {Console}
+ * @extends {TransportStream}
+ */
+module.exports = class Console extends TransportStream {
+  /**
+   * Constructor function for the Console transport object responsible for
+   * persisting log messages and metadata to a terminal or TTY.
+   * @param {!Object} [options={}] - Options for this instance.
+   */
+  constructor(options = {}) {
+    super(options);
+
+    // Expose the name of this Transport on the prototype
+    this.name = options.name || 'console';
+    this.stderrLevels = this._stringArrayToSet(options.stderrLevels);
+    this.consoleWarnLevels = this._stringArrayToSet(options.consoleWarnLevels);
+    this.eol = options.eol || os.EOL;
+
+    this.setMaxListeners(30);
+  }
+
+  /**
+   * Core logging method exposed to Winston.
+   * @param {Object} info - TODO: add param description.
+   * @param {Function} callback - TODO: add param description.
+   * @returns {undefined}
+   */
+  log(info, callback) {
+    setTimeout(() => this.emit('logged', info), 1);
+
+    // Remark: what if there is no raw...?
+    if (this.stderrLevels[info[LEVEL]]) {
+      if (console._stderr) {
+        // Node.js maps `process.stderr` to `console._stderr`.
+        // eslint-disable-next-line no-underscore-dangle
+        console._stderr.write(`${info[MESSAGE]}${this.eol}`);
+      } else {
+        // console.error adds a newline
+        console.error(info[MESSAGE]);
+      }
+
+      if (callback) {
+        callback(); // eslint-disable-line callback-return
+      }
+      return;
+    } if (this.consoleWarnLevels[info[LEVEL]]) {
+      // eslint-disable-next-line no-underscore-dangle
+      if (console._stderr) {
+        // Node.js maps `process.stderr` to `console._stderr`.
+        // in Node.js console.warn is an alias for console.error
+        console._stderr.write(`${info[MESSAGE]}${this.eol}`);
+      } else {
+        // console.warn adds a newline
+        console.warn(info[MESSAGE]);
+      }
+
+      if (callback) {
+        callback(); // eslint-disable-line callback-return
+      }
+      return;
+    }
+
+    // eslint-disable-next-line no-underscore-dangle
+    if (console._stdout) {
+      // Node.js maps `process.stdout` to `console._stdout`.
+      // eslint-disable-next-line no-underscore-dangle
+      console._stdout.write(`${info[MESSAGE]}${this.eol}`);
+    } else {
+      // console.log adds a newline.
+      console.log(info[MESSAGE]);
+    }
+
+    if (callback) {
+      callback(); // eslint-disable-line callback-return
+    }
+  }
+
+  /**
+   * Returns a Set-like object with strArray's elements as keys (each with the
+   * value true).
+   * @param {Array} strArray - Array of Set-elements as strings.
+   * @param {?string} [errMsg] - Custom error message thrown on invalid input.
+   * @returns {Object} - TODO: add return description.
+   * @private
+   */
+  // eslint-disable-next-line no-underscore-dangle
+  _stringArrayToSet(strArray, errMsg) {
+    if (!strArray) return {};
+
+    // eslint-disable-next-line no-param-reassign
+    errMsg = errMsg || 'Cannot make set from type other than Array of string elements';
+
+    if (!Array.isArray(strArray)) {
+      throw new Error(errMsg);
+    }
+
+    return strArray.reduce((set, el) => {
+      if (typeof el !== 'string') {
+        throw new Error(errMsg);
+      }
+      // eslint-disable-next-line no-param-reassign
+      set[el] = true;
+
+      return set;
+    }, {});
+  }
+};

src/logger.js → src/logger/index.js

@@ -1,5 +1,6 @@
 const util = require('util');
 const winston = require('winston');
+const Console = require('./console');
 
 const LOG_LEVEL = process.env.LOG_LEVEL || 'info';
 
@@ -14,7 +15,7 @@ const LOG_LEVEL = process.env.LOG_LEVEL || 'info';
 const logger = winston.createLogger({
   level: LOG_LEVEL,
   transports: [
-    new winston.transports.Console({
+    new Console({
       format: winston.format.combine(
         {
           transform: (info) => {