Optional chaining, but for a variable?

For something like the following:

"use strict";
let a = 1;
console.log(eval(`
    a++; 
    let b=4;
`));
console.log(`a=${a}, b=${b}`);
// ReferenceError: b is not defined

Is it possible to do something where it prints undefined or something if the variable is not there instead of throwing an error? Something conceptually like:

console.log(`a=${a}, b=$?.{b}`)