use boolean flag to ensure serializers are applied once

[emmyakin]

var logger = pino({
  serializers: {
    extras(data) {
      return { serializedExtras: data };
    },
  },
  browser: {
    serialize: ['extras'],
    asObject: true,
    transmit: {
      send(level, o) {
        is(o.messages[0].extras.serializedExtras, 'world');
      },
    },
  },
})

When opt.browser.transmit is defined, serializers are not applied to write

Conditions when serializers should be applied

• when opts.serialize is true or defined
  • serializers should be applied to write and transmit operations
• when opts.serialize is false or undefined
  • serializers should be applied to transmit operation only

[jsumners]

I am not following. Can you please provide a direct statement of the problem this is solving?

[mcollina]

lgtm

[emmyakin]

@jsumners

I am not following. Can you please provide a direct statement of the problem this is solving?

Sure

I had created this PR #1971 to fix serializers being applied twice to logs, i.e, before write and in transmit

The fix only applies serializers if transmit is not defined, which breaks the original implementation, where we want apply serializers for write operations even if transmit is defined, but options.serialize is true