Sha256: 5d0cea8b6845a331799318962c2df7cdcc854f6a18dbd217b54000494a3223ed
Contents?: true
Size: 884 Bytes
Versions: 30
Compression:
Stored size: 884 Bytes
Contents
"use strict";
var isPrototype = require("../prototype/is");
// In theory we could rely on Symbol.toStringTag directly,
// still early native implementation (e.g. in FF) predated symbols
var objectToString = Object.prototype.toString
, objectTaggedString = objectToString.call(Promise.resolve());
module.exports = function (value) {
if (!value) return false;
// Sanity check (reject objects which do not expose common Promise interface)
try {
if (typeof value.then !== "function") return false;
if (typeof value["catch"] !== "function") return false;
} catch (error) {
return false;
}
// Ensure its native Promise object (has [[PromiseState]] slot)
// Note: it's not 100% precise as string tag may be overriden
// and other objects could be hacked to expose it
if (objectToString.call(value) !== objectTaggedString) return false;
return !isPrototype(value);
};
Version data entries
30 entries across 29 versions & 2 rubygems