Returns the key for a specified symbol.
Syntax
Symbol.keyFor(sym);
Parameters
sym
Required. The symbol object.
Remarks
This method searches for the symbol in the global symbol registry.
Example
// Local symbol
var sym1 = Symbol("desc");
// Global symbol
var sym2 = Symbol.for("desc");
console.log(Symbol.keyFor(sym1)):
console.log(Symbol.keyFor(sym2));
// Output:
// undefined
// desc
Requirements
Supported in Microsoft Edge (Edge browser). Also supported in Store apps (Microsoft Edge on Windows 10). See Version Information.
Not supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards, Internet Explorer 11 standards. Not supported in Windows 8.1.

