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'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
exports['default'] = symbolObservablePonyfill;
function symbolObservablePonyfill(root) {
var result;
var _Symbol = root.Symbol;
if (typeof _Symbol === 'function') {
if (_Symbol.observable) {
result = _Symbol.observable;
} else {
if (typeof _Symbol['for'] === 'function') {
// This just needs to be something that won't trample other user's Symbol.for use
// It also will guide people to the source of their issues, if this is problematic.
// META: It's a resource locator!
result = _Symbol['for']('https://github.com/benlesh/symbol-observable');
} else {
// Symbol.for didn't exist! The best we can do at this point is a totally
// unique symbol. Note that the string argument here is a descriptor, not
// an identifier. This symbol is unique.
result = _Symbol('https://github.com/benlesh/symbol-observable');
}
try {
_Symbol.observable = result;
} catch (err) {
// Do nothing. In some environments, users have frozen `Symbol` for security reasons,
// if it is frozen assigning to it will throw. In this case, we don't care, because
// they will need to use the returned value from the ponyfill.
}
}
} else {
result = '@@observable';
}
return result;
};
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