Demo showing the use of minimumFractionDigits
The fraction is padded with zeros due to having less digits than those specified.
JavaScript
console.log(new Intl.NumberFormat("en", { minimumFractionDigits: 3 }).format(.1)) // 0.100
console.log(new Intl.NumberFormat("en", { minimumFractionDigits: 3 }).format(.1)) // 0.100