Function onWarning

lib/internal/process/warning.js:90–133

(warning)

let disableWarningSet;

function onWarning(warning) {
  if (!disableWarningSet) {
    disableWarningSet = new SafeSet();
    const disableWarningValues = getOptionValue('--disable-warning');
    for (let i = 0; i < disableWarningValues.length; i++) {
      disableWarningSet.add(disableWarningValues[i]);
    }
  }
  if ((warning?.code && disableWarningSet.has(warning.code)) ||
      (warning?.name && disableWarningSet.has(warning.name))) return;

  if (!(warning instanceof Error)) return;

  const isDeprecation = warning.name === 'DeprecationWarning';
  if (isDeprecation && process.noDeprecation) return;
  const trace = process.traceProcessWarnings ||
                (isDeprecation && process.traceDeprecation);
  let msg = `(${process.release.name}:${process.pid}) `;
  if (warning.code)
    msg += `[${warning.code}] `;
  if (trace && warning.stack) {
    msg += `${warning.stack}`;
  } else {
    msg +=
      typeof warning.toString === 'function' ?
        `${warning.toString()}` :
        ErrorPrototypeToString(warning);
  }
  if (typeof warning.detail === 'string') {
    msg += `\n${warning.detail}`;
  }
  if (!trace && !traceWarningHelperShown) {
    const flag = isDeprecation ? '--trace-deprecation' : '--trace-warnings';
    const argv0 = require('path').basename(process.argv0 || 'node', '.exe');
    msg += `\n(Use \`${argv0} ${flag} ...\` to show where the warning ` +
           'was created)';
    traceWarningHelperShown = true;
  }
  const warningFile = lazyOption();
  if (warningFile) {
    return writeToFile(msg);
  }
  writeOut(msg);
}

// process.emitWarning(error)
// process.emitWarning(str[, type[, code]][, ctor])