function abbrNum(number, decPlaces) {
// 2 decimal places => 100, 3 => 1000, etc
decPlaces = Math.pow(10, decPlaces);
// Enumerate number abbreviations
var abbrev = ["k", "m", "b", "t"];
// Go through the array backwards, so we do the largest first
for (var i = abbrev.length - 1; i >= 0; i--) {
// Convert array index to "1000", "1000000", etc
var size = Math.pow(10, (i + 1) * 3);
// If the number is bigger or equal do the abbreviation
if (size <= number) {
// Here, we multiply by decPlaces, round, and then divide by decPlaces.
// This gives us nice rounding to a particular decimal place.
number = Math.round(number * decPlaces / size) / decPlaces;
// Handle special case where we round up to the next abbreviation
if ((number == 1000) && (i < abbrev.length - 1)) {
number = 1;
i++;
}
// Add the letter for the abbreviation
number += abbrev[i];
// We are done... stop
break;
}
}
return number;
}
console.log(abbrNum(1200, 3))