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- "use strict";
-
- var isPrototype = require("../prototype/is")
- , isPlainObject = require("../plain-object/is");
-
- var objectToString = Object.prototype.toString;
-
- // Recognize host specific errors (e.g. DOMException)
- var errorTaggedStringRe = /^\[object .*(?:Error|Exception)\]$/
- , errorNameRe = /^[^\s]*(?:Error|Exception)$/;
-
- module.exports = function (value) {
- if (!value) return false;
-
- var name;
- // Sanity check (reject objects which do not expose common Error interface)
- try {
- name = value.name;
- if (typeof name !== "string") return false;
- if (typeof value.message !== "string") return false;
- } catch (error) {
- return false;
- }
-
- // Ensure its a native-like Error object
- // (has [[ErrorData]] slot, or was created to resemble one)
- // Note: It's not a 100% bulletproof check of confirming that as:
- // - In ES2015+ string tag can be overriden via Symbol.toStringTag property
- // - Host errors do not share native error tag. Still we rely on assumption that
- // tag for each error will end either with `Error` or `Exception` string
- // - In pre ES2015 era, no custom errors will share the error tag.
- if (!errorTaggedStringRe.test(objectToString.call(value))) {
- // Definitely not an ES2015 error instance, but could still be an error
- // (created via e.g. CustomError.prototype = Object.create(Error.prototype))
- try {
- if (name !== value.constructor.name) return false;
- } catch (error) {
- return false;
- }
- if (!errorNameRe.test(name)) return false;
- if (isPlainObject(value)) return false;
- }
-
- return !isPrototype(value);
- };
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