[{name: 'вася', parents: []}, {name: 'петя', parents: []}]
ну и так далее.[{name: 'вася', number: 1}, {name: 'петя', number: 2}]
let x = [{name: 'вася', parents: []}, {name: 'петя', parents: []}];
let y = x.map((el, i) => ({name: el.name, number: i+1}))
jsfiddle.net/n463x5ak