pino/test/types/pino-type-only.test-d.ts

super fast, all natural json logger

import { expectAssignable, expectType, expectNotAssignable } from 'tsd'

import pino from '../../'
import type {
  LevelWithSilent,
  Logger,
  LogFn,
  DestinationStreamWithMetadata,
  Level,
  LevelOrString,
  LevelWithSilentOrString,
  LoggerExtras,
  LoggerOptions,
} from '../../pino'

// NB: can also use `import * as pino`, but that form is callable as `pino()`
// under `esModuleInterop: false` or `pino.default()` under `esModuleInterop: true`.
const log = pino()
expectAssignable<LoggerExtras>(log)
expectType<Logger>(log)
expectType<LogFn>(log.info)

expectType<Parameters<typeof log.isLevelEnabled>>([log.level])

const level: Level = 'debug'
expectAssignable<string>(level)

const levelWithSilent: LevelWithSilent = 'silent'
expectAssignable<string>(levelWithSilent)

const levelOrString: LevelOrString = 'myCustomLevel'
expectAssignable<string>(levelOrString)
expectNotAssignable<pino.Level>(levelOrString)
expectNotAssignable<pino.LevelWithSilent>(levelOrString)
expectAssignable<pino.LevelWithSilentOrString>(levelOrString)

const levelWithSilentOrString: LevelWithSilentOrString = 'myCustomLevel'
expectAssignable<string>(levelWithSilentOrString)
expectNotAssignable<pino.Level>(levelWithSilentOrString)
expectNotAssignable<pino.LevelWithSilent>(levelWithSilentOrString)
expectAssignable<pino.LevelOrString>(levelWithSilentOrString)

function createStream (): DestinationStreamWithMetadata {
  return { write () {} }
}

const stream = createStream()
// Argh. TypeScript doesn't seem to narrow unless we assign the symbol like so, and tsd seems to
// break without annotating the type explicitly
const needsMetadata: typeof pino.symbols.needsMetadataGsym = pino.symbols.needsMetadataGsym
if (stream[needsMetadata]) {
  expectType<number>(stream.lastLevel)
}

const loggerOptions: LoggerOptions = {
  browser: {
    formatters: {
      log (obj) {
        return obj
      },
      level (label, number) {
        return { label, number }
      },
    },
  },
}

expectType<LoggerOptions>(loggerOptions)

// Reference: https://github.com/pinojs/pino/issues/2285
const someConst = 'test' as const
pino().error({}, someConst)
const someFunc = <T extends typeof someConst>(someConst: T) => {
  pino().error({}, someConst)
}