1const map = {"a": 1, "b": 2, "c": 3};
2const mapped = Object.entries(map).map(([k,v]) => `${k}_${v}`);
3console.log(mapped);

1['elem', 'another', 'name'].map((value, index, originalArray) => { 
2  console.log(.....)
3});

1m.set('color', 'red')
2m.set('age', 2)
3