dx: add type hints to math utils

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: davidstackio

src/runtime/utils/math.ts

@@ -1,9 +1,9 @@
-export function toPercentage(val: number, decimals = 0) {
+export function toPercentage(val: number, decimals = 0): string {
   const percentage = (val * 100).toFixed(decimals)
   return `${percentage}%`
 }
 
-export function roundToFixed(val: number | string, positions = 2) {
+export function roundToFixed(val: number | string, positions = 2): number {
   let text = 0
   if (typeof val === 'string') {
     text = +Number.parseFloat(val).toFixed(positions)