SOURCE

function executeCode(obj, params) {
  const str = `(${params})=>${obj.slice(1)}`
  return new Function(`"use strict";return (${str})`)()(Function('"use strict";return (' + params + ')')())
}
const cus = {
    xx:'c',
    query:{
        a:123,
        b:{
            c:'cccc'
        }
    }
}
console.log(cus.query.b.c)
console.log(executeCode('=cus.query.b.c','cus'))
console.log(executeCode('=cus["query"]["a"]','cus'))
const cc = 'c'
console.log(executeCode('=cus["query"]["b"][cus.xx]','cus'))