git.squeep.com Git - urlittler/blob - src/logger.js

   1 'use strict';
   2
   3 /**
   4  * Log as JSON to stdout/stderr.
   5  */
   6
   7 const common = require('./common');
   8
   9 // This is uncomfortable, but is the simplest way to let logging work for BigInts.
  10 // TODO: revisit with better solution
  11 BigInt.prototype.toJSON = function() {
  12   return this.toString();
  13 }
  14
  15 // Also uncomfortable
  16 Object.defineProperty(Error.prototype, 'toJSON', {
  17   configurable: true,
  18   value: function () {
  19     const result = {};
  20     const dupKey = function (key) {
  21       // eslint-disable-next-line security/detect-object-injection
  22       result[key] = this[key];
  23     };
  24     Object.getOwnPropertyNames(this).forEach(dupKey, this);
  25     return result;
  26   },
  27 });
  28
  29 const defaultOptions = {
  30   ignoreBelowLevel: 'debug',
  31   backend: console,
  32 };
  33
  34 class Logger {
  35   constructor(options = {}) {
  36     common.setOptions(this, defaultOptions, options);
  37
  38     this.logLevels = [
  39       'error',
  40       'warn',
  41       'info',
  42       'log',
  43       'debug',
  44     ];
  45
  46     const ignoreLevelIdx = this.logLevels.indexOf(this.ignoreBelowLevel);
  47     this.logLevels.forEach((level) => {
  48       // eslint-disable-next-line security/detect-object-injection
  49       this[level] = (this.logLevels.indexOf(level) > ignoreLevelIdx) ?
  50         () => {} :
  51         Logger.levelTemplateFn(this.backend, level);
  52     });
  53   }
  54
  55   static levelTemplateFn(backend, level) {
  56     return function (...args) {
  57       // eslint-disable-next-line security/detect-object-injection
  58       backend[level](Logger.payload(level, ...args));
  59     };
  60   }
  61
  62   static payload(level, scope, message, data, ...other) {
  63     return JSON.stringify({
  64       timestamp: Date.now(),
  65       level: level,
  66       scope: scope || '[unknown]',
  67       message: message || '',
  68       data: data || {},
  69       ...(other.length && { other }),
  70     });
  71   }
  72 }
  73
  74 module.exports = Logger;