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Babel + JSX

const data = {
  "7": ["9149", "9139", "10455", "17208"],
  "7.5": ["9140", "9150", "10456", "17209"],
  "8": ["2684", "9141", "10457", "17210"],
  "8.5": ["9142", "10444", "10458", "17211"],
  "9": ["2685", "9143", "10459", "17212"],
  "9.5": ["10443", "9144", "10460", "17213"]
}

const data2 = {
  "_7": ["9149", "9139", "10455", "17208"],
  "_7.5": ["9140", "9150", "10456", "17209"],
  "_8": ["2684", "9141", "10457", "17210"],
  "_8.5": ["9142", "10444", "10458", "17211"],
  "_9": ["2685", "9143", "10459", "17212"],
  "_9.5": ["10443", "9144", "10460", "17213"]
}




const m = new Map()
for (let k in data) console.log(k)
console.log(Object.keys(data))

for (let k in data2) {
  console.log(k)
  m.set(k.replace('_', ''), data2[k])
}
console.log(Object.keys(data2))

console.log(m, m.keys());