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Don't use instanceof in lib/util.js "is" checks.

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While using `instanceof`, these functions could easily be faked with something
like:  Object.create(Date.prototype)

So let's just not use it at all. A little slower, but these functions are only
used in the REPL / for debugging so it's OK.

Fixes #1941.
Fixes #1942.
This commit is contained in:
Nathan Rajlich 2011-10-25 21:42:23 -07:00 committed by koichik
parent 194511ff1a
commit 2dbb470ea1
1 changed files with 7 additions and 9 deletions
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16
lib/util.js
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@ -378,31 +378,29 @@ function reduceToSingleString(output, base, braces) {
}
// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.
function isArray(ar) {
return ar instanceof Array ||
Array.isArray(ar) ||
(ar && ar !== Object.prototype && isArray(ar.__proto__));
return Array.isArray(ar) ||
(typeof ar === 'object' && objectToString(ar) === '[object Array]');
}
exports.isArray = isArray;
function isRegExp(re) {
return re instanceof RegExp ||
(typeof re === 'object' && objectToString(re) === '[object RegExp]');
return typeof re === 'object' && objectToString(re) === '[object RegExp]';
}
exports.isRegExp = isRegExp;
function isDate(d) {
return d instanceof Date ||
(typeof d === 'object' && objectToString(d) === '[object Date]');
return typeof d === 'object' && objectToString(d) === '[object Date]';
}
exports.isDate = isDate;
function isError(e) {
return e instanceof Error ||
(typeof e === 'object' && objectToString(e) === '[object Error]');
return typeof e === 'object' && objectToString(e) === '[object Error]';
}
exports.isError = isError;