var $ = obj => new Proxy({}, { get: (_, key) => key=='$' ? obj : $((obj||{})[key]) })
 
 
var hoge = { fuga: { piyo: 'boo', puyo: 123 } }
 
var $hoge = $(hoge)
 
 
x = $hoge.fuga.piyo.$   // 'boo'
x = $hoge.fuga2.payo.$  // undefined 
 
x = $hoge.fuga.puyo.$     // 123
x = $hoge.fuga2.poyo.$    // undefined
 
if (hoge && hoge.fuga && hoge.fuga.puyo === 123) {}
//↓
if ($hoge.fuga.puyo.$ === 123) {}
 
if (hoge && hoge.fuga && hoge.fuga.piyo && hoge.fuga.piyo.length > 2) {}
//↓
if ($hoge.fuga.piyo.length.$ > 2) {}

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