diff --git a/lib/internal/util.js b/lib/internal/util.js index 414d037a298ca6..ee550fad2e621c 100644 --- a/lib/internal/util.js +++ b/lib/internal/util.js @@ -12,6 +12,9 @@ const { arrow_message_private_symbol: kArrowMessagePrivateSymbolIndex, decorated_private_symbol: kDecoratedPrivateSymbolIndex } = internalBinding('util'); +const { + isNativeError +} = internalBinding('types'); const { errmap } = internalBinding('uv'); @@ -26,7 +29,10 @@ function removeColors(str) { } function isError(e) { - return objectToString(e) === '[object Error]' || e instanceof Error; + // An error could be an instance of Error while not being a native error + // or could be from a different realm and not be instance of Error but still + // be a native error. + return isNativeError(e) || e instanceof Error; } function objectToString(o) { diff --git a/lib/util.js b/lib/util.js index 63b34f48bfa896..8f7f3a92ddcf6f 100644 --- a/lib/util.js +++ b/lib/util.js @@ -42,10 +42,16 @@ const { const { deprecate, getSystemErrorName: internalErrorName, - isError, promisify, } = require('internal/util'); +const ReflectApply = Reflect.apply; + +function uncurryThis(func) { + return (thisArg, ...args) => ReflectApply(func, thisArg, args); +} +const objectToString = uncurryThis(Object.prototype.toString); + let CIRCULAR_ERROR_MESSAGE; let internalDeepEqual; @@ -443,7 +449,9 @@ module.exports = exports = { isRegExp, isObject, isDate, - isError, + isError(e) { + return objectToString(e) === '[object Error]' || e instanceof Error; + }, isFunction, isPrimitive, log, diff --git a/test/parallel/test-internal-util-helpers.js b/test/parallel/test-internal-util-helpers.js new file mode 100644 index 00000000000000..bf60cff9bda4be --- /dev/null +++ b/test/parallel/test-internal-util-helpers.js @@ -0,0 +1,37 @@ +// Flags: --expose-internals +'use strict'; + +require('../common'); +const assert = require('assert'); +const { types } = require('util'); +const { isError } = require('internal/util'); +const vm = require('vm'); + +// Special cased errors. Test the internal function which is used in +// `util.inspect()`, the `repl` and maybe more. This verifies that errors from +// different realms, and non native instances of error are properly detected as +// error while definitely false ones are not detected. This is different than +// the public `util.isError()` function which falsy detects the fake errors as +// actual errors. +{ + const fake = { [Symbol.toStringTag]: 'Error' }; + assert(!types.isNativeError(fake)); + assert(!(fake instanceof Error)); + assert(!isError(fake)); + + const err = new Error('test'); + const newErr = Object.create( + Object.getPrototypeOf(err), + Object.getOwnPropertyDescriptors(err)); + Object.defineProperty(err, 'message', { value: err.message }); + assert(types.isNativeError(err)); + assert(!types.isNativeError(newErr)); + assert(newErr instanceof Error); + assert(isError(newErr)); + + const context = vm.createContext({}); + const differentRealmErr = vm.runInContext('new Error()', context); + assert(types.isNativeError(differentRealmErr)); + assert(!(differentRealmErr instanceof Error)); + assert(isError(differentRealmErr)); +}