Using Symbol.iterator to update how (for of) loop iterates through an object

symbol.iterator.txt

const testingTeam = {
    lead: 'Alex', 
    engineer: 'Bill',
    // This is generator function 
    [Symbol.iterator]: function*  () {
        yield this.lead;
        yield this.engineer
    }
}

const engineeringTeam = {
    testingTeam,
    lead: 'Prashant',
    engineer: 'Sudarshan', 
    manager: 'Harshit', 
    // This is generator function     
    [Symbol.iterator]: function*  () {
        yield this.lead;
        yield this.engineer;
        yield this.manager;
        yield* this.testingTeam;
    }
}

let allEngineers = []
for(teamMember of engineeringTeam) {
    allEngineers.push(teamMember);
}
console.log(allEngineers)