I am running into an issue using type, fastify, and jest. A plugin I am usin

FastifyWarning not an instance of Error about process-warning HOT 2 CLOSED

jamestalton commented on July 30, 2024

FastifyWarning not an instance of Error

from process-warning.

Comments (2)

jamestalton commented on July 30, 2024

On further investigation... it seems that this is thrown when anything other than a string is passed to process.emitWarning
process.emitWarning(new Error('test'))

This might be a JEST thing...

from process-warning.

jamestalton commented on July 30, 2024

https://github.com/nodejs/node-auto-test/blob/b067260648eb34c5553856729db47482cc7b412d/lib/internal/process/warning.js

if (typeof warning === 'string') {
    warning = createWarningObject(warning, type, code, ctor, detail);
  } else if (!(warning instanceof Error)) {
    throw new ERR_INVALID_ARG_TYPE('warning', ['Error', 'string'], warning);
  }
  if (warning.name === 'DeprecationWarning') {
    if (process.noDeprecation)
      return;
    if (process.throwDeprecation) {
      // Delay throwing the error to guarantee that all former warnings were
      // properly logged.
      return process.nextTick(() => {
        throw warning;
      });
    }
  }

Apparently if the warning name in nodejs is 'DeprecationWarning' it handles differently.
Since many of the fastify warnings are deprecations, they should be updated to that style?
that way they can be ignored with process.noDeprecation or turned into thrown errors using process.throwDeprecation.

This works in my environment:

function emitWarning (code) {
  if (codes[code] === undefined) throw new Error(`The code '${code}' does not exist`)
  if (emittedWarnings.has(code) === true) return
  emittedWarnings.set(code, true)
  const error = new codes[code]()
  process.emitWarning(error.message, "DeprecationWarning", error.code)
}

(node:9771) [FSTDEP003] DeprecationWarning: You are using the legacy Content Type Parser function signature. Use the one suggested in the documentation instead.

from process-warning.

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