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24 lines
485 B
24 lines
485 B
'use strict'; |
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var callBound = require('call-bind/callBound'); |
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var $PromiseThen = callBound('Promise.prototype.then', true); |
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var Type = require('./Type'); |
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// https://ecma-international.org/ecma-262/6.0/#sec-ispromise |
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module.exports = function IsPromise(x) { |
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if (Type(x) !== 'Object') { |
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return false; |
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} |
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if (!$PromiseThen) { // Promises are not supported |
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return false; |
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} |
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try { |
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$PromiseThen(x); // throws if not a promise |
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} catch (e) { |
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return false; |
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} |
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return true; |
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};
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