Gets percentage rounds in TypeScript

main.test.ts

import { assertEquals } from "https://deno.land/[email protected]/testing/asserts.ts";
import { getPercentageRounds } from "./main.ts";

Deno.test(function getPercentageRoundsTest() {
  assertEquals(getPercentageRounds(0),    "⚪⚪⚪⚪⚪⚪⚪⚪⚪⚪");
  assertEquals(getPercentageRounds(0.04), "🔵⚪⚪⚪⚪⚪⚪⚪⚪⚪");
  assertEquals(getPercentageRounds(0.1),  "🔵⚪⚪⚪⚪⚪⚪⚪⚪⚪");
  assertEquals(getPercentageRounds(0.5),  "🔵🔵🔵🔵🔵⚪⚪⚪⚪⚪");
  assertEquals(getPercentageRounds(0.6),  "🔵🔵🔵🔵🔵🔵⚪⚪⚪⚪");
  assertEquals(getPercentageRounds(1),    "🔵🔵🔵🔵🔵🔵🔵🔵🔵🔵");
});

main.ts

export function getPercentageRounds(percentage: number) {
  if (percentage < 0 || percentage > 1) {
    throw new Error("Percentage must be between 0 and 1");
  }
  const fullRounds = Math.ceil(percentage * 10);
  const emptyRounds = 10 - fullRounds;
  const fullRoundsString = "🔵".repeat(fullRounds);
  const emptyRoundsString = "⚪".repeat(emptyRounds);
  return `${fullRoundsString}${emptyRoundsString}`;
}