Bunyan higher levels logging into lower level streams
<p>I am trying to use bunyan in my nodejs application, however I stuck with this bizarre behaviour.
Defining the logger like so:</p>

<pre><code>var info = bunyan.createLogger({
    name: 'Test',
    streams: [
        {
            path: './logger/fatal.log',
            level: 'fatal'
        },
        {
            path: './logger/error.log',
            level: 'error'
        },
        {
            path: './logger/warn.log',
            level: 'warn'
        },
        {
            path: './logger/info.log',
            level: 'info'
        },
        {
            path: './logger/debug.log',
            level: 'debug'
        },
        {
            path: './logger/trace.log',
            level: 'trace'
        }
    ]
});
</code></pre>

<p>And I am calling them in a function like so:</p>

<pre><code>var func = function () {
    info.fatal("FATAL!");
    info.error("ERROR!");
    info.warn("WARN!");
    info.debug("DEBUG!");
    info.info("INFO");
    info.trace("TRACE");
}
</code></pre>

<p>Now the predictable behaviour would be 
<strong>fatal.log</strong> has <code>{"name":"Test","hostname":"ENIGMA","pid":16793,"level":60,"msg":"FATAL!","time":"2016-01-21T09:12:34.293Z","v":0}</code></p>

<p>and <strong>error.log</strong> has <code>{"name":"Test","hostname":"ENIGMA","pid":16793,"level":50,"msg":"ERROR!","time":"2016-01-21T09:12:34.295Z","v":0}</code>
and so forth.</p>

<p>However, on my application,
<strong>fatal.log</strong> has <code>{"name":"Test","hostname":"ENIGMA","pid":16793,"level":60,"msg":"FATAL!","time":"2016-01-21T09:12:34.293Z","v":0}</code></p>

<p><strong>error.log</strong> has 
<code>{"name":"Test","hostname":"ENIGMA","pid":16793,"level":60,"msg":"FATAL!","time":"2016-01-21T09:12:34.293Z","v":0}
{"name":"Test","hostname":"ENIGMA","pid":16793,"level":50,"msg":"ERROR!","time":"2016-01-21T09:12:34.295Z","v":0}</code></p>

<p><strong>warn.log</strong> has
<code>{"name":"Test","hostname":"ENIGMA","pid":16793,"level":60,"msg":"FATAL!","time":"2016-01-21T09:12:34.293Z","v":0}
{"name":"Test","hostname":"ENIGMA","pid":16793,"level":50,"msg":"ERROR!","time":"2016-01-21T09:12:34.295Z","v":0}
{"name":"Test","hostname":"ENIGMA","pid":16793,"level":40,"msg":"WARN!","time":"2016-01-21T09:12:34.296Z","v":0}</code></p>

<p>and so forth.</p>

<p>The higher level logs are getting into the lower streams.
How do I prevent this behaviour and make each level log into its own specific file?
(I have also reported an issue at <a href="https://github.com/trentm/node-bunyan/issues/334" rel="nofollow">node-bunyan</a>)</p>