customProps causes TypeError: logger[stringifySym] is not a function

[jniemin]

customProps option is causing application to crash with

TypeError: logger[stringifySym] is not a function
  /Users/xxxx/node_modules/pino-http/logger.js:106
  const customPropBindingStr = logger[stringifySym](customPropBindings).replace(/[{}]/g, '')

After doing some debugging, seems that pino.child(bindings) call returns child logger which doesn't contain most of the symbols, including Symbol(pino.stringify).

You can see this by:

const logger = pino(pinoOptions);
console.log({logger})
const child = logger.child({});
console.log({child})

Internally pino-http does create child logger and stringify symbol is expected to be included later in the logger (https://github.com/pinojs/pino-http/blob/master/logger.js#L106)

 if (customPropBindings) {
      const customPropBindingStr = logger[stringifySym](customPropBindings).replace(/[{}]/g, '')
      const customPropBindingsStr = logger[chindingsSym]
      if (!customPropBindingsStr.includes(customPropBindingStr)) {
        log = logger.child(customPropBindings)
      }
    }

I was testing with pino 8.16.2 and pino-http 8.5.1