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