Nostradamus Prophecy Machine


    1.1.23 • Public • Published


    Transform stream for Hapi Good process monitoring. Modify the incoming object stream with your own mapping functions.

    Build Status Coverage Status dependencies Status Maintainability node code style License Status

    Tested with

    • Node 12/14/15, Hapi 19/20, Good 9
    • Node 10, Hapi 18, Good 8


    npm install good-map


    Your Good logging configuration may look like this:

    const Hapi = require('@hapi/hapi');
    const Good = require('@hapi/good'),
    const server = new Hapi.Server();
    const options = {
      reporters: {
        myConsoleReporter: [{
          module: '@hapi/good-squeeze',
          name: 'Squeeze',
          args: [{ log: '*', response: '*' }],
        }, {
          module: 'good-map',
          args: [{
            events: ['log'],
            tags: ['error'],
            map: {
              timestamp: (ms) => moment(ms).utc().format(),
              'database.password': () => '***',
              'error.stack': (stack) => truncate(stack),
            observe: (item) => {
              item.service = 'foo';
        }, {
          module: '@hapi/good-console',
        }, 'stdout'],
    await server.register({
      plugin: Good,
    await server.start();


    The good-map transform stream can be placed anywhere in the pipeline where log values are still objects, e.g., after Squeeze.

    args in the Good configuration for good-map is an array with two arguments which are passed to GoodMap(rules, [options]):

    • rules: An object with the following parameters (all optional):
      • events: A list of Hapi server event types, e.g., ['request'], for filtering purposes.
      • tags: A list of event tags, e.g., ['error'], for filtering purposes.
      • map: An object that maps the log item's properties (including deep properties separated by dots), e.g., timestamp or 'error.message' to a mapping function (synchronous). It has the form (value) => 'newValue', e.g., () => '***' or str => str.toUpperCase(). If a property does not exist (before), it is not set. If the mapping function returns undefined, the property is deleted. If the mapping function throws an error, the error is ignored. For full flexibility, the second parameter provides access to the complete log item: (value, item) => ....
      • observe: Listen to the complete log item as it appears in the stream. The observer function (synchronous) has the form (item) => { ... }. Use this hook to read and write to the log item. If the observer function throws an error, the error is ignored.
    • options: An optional configuration object that gets passed to the Node Stream.Transform constructor. objectMode is always true.


    npm i good-map

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    • frankthelen