get-depth-prop.js

function getPros(o, prop){
    if(o.hasOwnProperty(prop)){
        return o[prop];
    }
    let v = null;

    Object.keys(o).forEach((item) => {
        if(typeof o[item] === 'object'){
            v = getPros(o[item], prop)
        }
    });

    return v;
}

let a = {t1: 1};
let b = {t2: 2};
let c = {t3: {
    d: b
}};

console.log(getPros(c, 't2')) // 2

let b = {t2: 555};
let c = {t3: {
    d: {e:b}
}};
console.log(getPros(c, 't2')) // 555