Depurando o Express
Para ver todos os logs interno usados no Express, configure a variável de ambiente DEBUG para express:* ao ativar seu aplicativo.
$ DEBUG=express:* node index.js No Windows, use o comando correspondente.
> $env:DEBUG = "express:*"; node index.js Executar este comando no aplicativo padrão gerado pelo express generator imprime a seguinte saída:
$ DEBUG=express:* node ./bin/www express:router:route new / +0ms express:router:layer new / +1ms express:router:route get / +1ms express:router:layer new / +0ms express:router:route new / +1ms express:router:layer new / +0ms express:router:route get / +0ms express:router:layer new / +0ms express:application compile etag weak +1ms express:application compile query parser extended +0ms express:application compile trust proxy false +0ms express:application booting in development mode +1ms express:router use / query +0ms express:router:layer new / +0ms express:router use / expressInit +0ms express:router:layer new / +0ms express:router use / favicon +1ms express:router:layer new / +0ms express:router use / logger +0ms express:router:layer new / +0ms express:router use / jsonParser +0ms express:router:layer new / +1ms express:router use / urlencodedParser +0ms express:router:layer new / +0ms express:router use / cookieParser +0ms express:router:layer new / +0ms express:router use / stylus +90ms express:router:layer new / +0ms express:router use / serveStatic +0ms express:router:layer new / +0ms express:router use / router +0ms express:router:layer new / +1ms express:router use /users router +0ms express:router:layer new /users +0ms express:router use / <anonymous> +0ms express:router:layer new / +0ms express:router use / <anonymous> +0ms express:router:layer new / +0ms express:router use / <anonymous> +0ms express:router:layer new / +0ms Quando uma solicitação é feita em seguida para o aplicativo, você verá os logs especificados no código do Express:
express:router dispatching GET / +4h express:router query : / +2ms express:router expressInit : / +0ms express:router favicon : / +0ms express:router logger : / +1ms express:router jsonParser : / +0ms express:router urlencodedParser : / +1ms express:router cookieParser : / +0ms express:router stylus : / +0ms express:router serveStatic : / +2ms express:router router : / +2ms express:router dispatching GET / +1ms express:view lookup "index.pug" +338ms express:view stat "/projects/example/views/index.pug" +0ms express:view render "/projects/example/views/index.pug" +1ms Para ver os logs apenas da implementação do roteador configure o valor de DEBUG para express:router. Do mesmo modo, para ver os logs apenas da implementação do aplicativo configure o valor de DEBUG para express:application, e assim por diante.
Aplicativos gerados pelo express
Um aplicativo gerado pelo comando express também usa o módulo de debug e o seu namespace de depuração está com o escopo definido para o nome do aplicativo.
Por exemplo, se você gerou o aplicativo com o $ express sample-app, é possível ativar as instruções de depuração com o seguinte comando:
$ DEBUG=sample-app:* node ./bin/www É possível especificar mais do que um namespace de depuração designando uma lista de nomes separados por vírgulas:
$ DEBUG=http,mail,express:* node index.js Advanced options
When running through Node.js, you can set a few environment variables that will change the behavior of the debug logging:
| Name | Purpose |
|---|---|
DEBUG | Enables/disables specific debugging namespaces. |
DEBUG_COLORS | Whether or not to use colors in the debug output. |
DEBUG_DEPTH | Object inspection depth. |
DEBUG_FD | File descriptor to write debug output to. |
DEBUG_SHOW_HIDDEN | Shows hidden properties on inspected objects. |
Note
The environment variables beginning with DEBUG_ end up being converted into an Options object that gets used with %o/%O formatters. See the Node.js documentation for util.inspect() for the complete list.