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Diffstat (limited to 'node_modules/es-abstract/2016/IsPromise.js')
-rw-r--r--node_modules/es-abstract/2016/IsPromise.js24
1 files changed, 24 insertions, 0 deletions
diff --git a/node_modules/es-abstract/2016/IsPromise.js b/node_modules/es-abstract/2016/IsPromise.js
new file mode 100644
index 000000000..e8e92a2b8
--- /dev/null
+++ b/node_modules/es-abstract/2016/IsPromise.js
@@ -0,0 +1,24 @@
+'use strict';
+
+var callBound = require('../helpers/callBound');
+
+var $PromiseThen = callBound('Promise.prototype.then', true);
+
+var Type = require('./Type');
+
+// https://www.ecma-international.org/ecma-262/6.0/#sec-ispromise
+
+module.exports = function IsPromise(x) {
+ if (Type(x) !== 'Object') {
+ return false;
+ }
+ if (!$PromiseThen) { // Promises are not supported
+ return false;
+ }
+ try {
+ $PromiseThen(x); // throws if not a promise
+ } catch (e) {
+ return false;
+ }
+ return true;
+};