com.google.javascript.jscomp.js.es6.conformance.js Maven / Gradle / Ivy
/*
* Copyright 2017 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'require util/global';
/**
* @fileoverview Check one of the most obscure features of ES6 as a proxy
* for full conformance. If this is enabled, this test is used instead of
* larger, more specific conformance tests.
*/
/**
* Check ES6 conformance by checking an obscure detail of Proxy that
* wasn't implemented correctly until after all other ES6 features in
* most browsers.
* @return {boolean} Whether Proxy works correctly.
* @suppress {reportUnknownTypes}
*/
$jscomp.checkEs6ConformanceViaProxy = function() {
try {
var proxied = {};
var proxy = Object.create(new $jscomp.global['Proxy'](proxied, {
'get': function (target, key, receiver) {
return target == proxied && key == 'q' && receiver == proxy;
}
}));
return proxy['q'] === true;
} catch (err) {
return false;
}
};
/**
* If this is true, assume that a runtime which implements Proxy also
* implements the rest of the ECMAScript 2015 spec.
* @define {boolean}
*/
$jscomp.USE_PROXY_FOR_ES6_CONFORMANCE_CHECKS = false;
/**
* Whether the runtime implements the entire ECMAScript 2015 spec.
* @const {boolean}
*/
$jscomp.ES6_CONFORMANCE =
$jscomp.USE_PROXY_FOR_ES6_CONFORMANCE_CHECKS &&
$jscomp.checkEs6ConformanceViaProxy();