[BUG] trackTrace with ICustomProperties does not allow numeric values

I’m using applicationinsights-web with an Angular application. When logging a trace message using a custom properties object, any values which are not strings are ignored (with no error message). If I intercept the properties object and convert the values to strings then all the values are logged as expected. As far as I understand the index signature { key: string]: any } should allow numeric values to be logged?

Example of logging code with the workaround in place:

logTrace(
    message: string,
    severityLevel: SeverityLevel,
    properties?: { [key: string]: any }
  ) {
    // convert the properties object into keys with only string values
    Object.keys(properties).forEach(k => { properties[k] = properties[k].toString() })

    this.appInsights.trackTrace(
      { message: message, severityLevel: severityLevel },
      properties
    );
  }

Steps to Reproduce

• Windows/Chrome
• “@microsoft/applicationinsights-web”: “^2.7.0”
• SDK initialised like this:

this.appInsights = new ApplicationInsights({
    config: {
      connectionString: config.connectionStringAI,
      enableAutoRouteTracking: true,
      disableFetchTracking: false, 
      enableUnhandledPromiseRejectionTracking: true, 
    },
  });
  this.appInsights.loadAppInsights();
  this.appInsights.addTelemetryInitializer((envelope) => {
    envelope.data.appVersion = environment.appVersion;
    envelope.tags['ai.cloud.role'] = 'IonicAngularApp'; 
  });

Issues #1737 and #1057 may be related?

Expected behavior Numeric or boolean or other types should be logged against object keys (strings) in object with type ICustomProperties

[MSNev]

@Karlie-777 can you please investigate this a bit further (create a repro and a unit test for the issue and then address any issues).

For reference get flattened, stringified or ignored altogether. is the design but the ignored should be causing some logging / failures (for exceptions), this may only currently be documented in the code so we should add this somewhere more visible as per @baxxos suggestion.

I don’t think we want to change the ICustomProperties to be specific as I’m aware of several internal / external users the use the get flattened (JSON.stringify()) functionality of the any aspect.

[baxxos]

The properties interface is defined in a way that allows us to pass in any kind of value - e.g. a deeply nested object, but from my experience, it only works reliably with strings. More complex values will either get flattened, stringified or ignored altogether.

Example:

appInsights?.trackTrace({
  message,
  severityLevel: SeverityLevel.Information,
  properties: {
    level1: { level2: { level3: 'level3value' } },
  },
})

results in:

It would be nice to define the ICustomProperties in a way that would reflect only the supported data types or describe the value processing behavior in documentation.