min and max significant digits

Test using minimumSignificantDigits and maximumSignificantDigits.

JavaScript

var mn1Mx3 = new Intl.NumberFormat("fr", { 
    minimumSignificantDigits: 1,
    maximumSignificantDigits: 3
});

console.log(mn1Mx3.format(1.501)); // 1.5
console.log(mn1Mx3.format(25499.99)); // 25,500