Setting up symbol-valued constants via proxies — 2ality.com

Dean Tribble (via Rob Palmer) has come up with a neat trick to create constants whose values are strings with their names. With a minor change, we can use it to set up symbol-valued constants. Setting up constants   const SymbolFactory = new Proxy({}, { get: (_target, propKey, _receiver) => Symbol(propKey) }); const {red, green, blue} = SymbolFactory; assert.equal( typeof red, 'symbol' ); assert.equal( String(red), 'Symbol(red)' ); How does it work?   Each property of the pattern that object-destructures SymbolFactory, triggers a property get operation. Therefore, line B is equivalent to: const red = SymbolFactory.red; const green = SymbolFactory.green; const blue = SymbolFactory.blue; The method in line A intercepts each of these get operations. Among other information, it is provided with the key of the relevant property. It then creates and returns a symbol whose description is the property key. Further reading  

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