Function emitWarning

lib/internal/process/warning.js:138–181

(warning, type, code, ctor)

// process.emitWarning(str[, type[, code]][, ctor])
// process.emitWarning(str[, options])
function emitWarning(warning, type, code, ctor) {
  // Fast path to avoid memory allocation,
  // this doesn't eliminate the other if a few lines below
  if (process.noDeprecation && type === 'DeprecationWarning') {
    return;
  }
  let detail;
  if (type !== null && typeof type === 'object' && !ArrayIsArray(type)) {
    ctor = type.ctor;
    code = type.code;
    if (typeof type.detail === 'string')
      detail = type.detail;
    type = type.type || 'Warning';
  } else if (typeof type === 'function') {
    ctor = type;
    code = undefined;
    type = 'Warning';
  }
  if (type !== undefined)
    validateString(type, 'type');
  if (typeof code === 'function') {
    ctor = code;
    code = undefined;
  } else if (code !== undefined) {
    validateString(code, 'code');
  }
  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;
      });
    }
  }
  process.nextTick(doEmitWarning, warning);
}

function emitWarningSync(warning, type, code, ctor) {
  process.emit('warning', createWarningObject(warning, type, code, ctor));