TypeScript / JavaScript ASCII progress bar function using semi-opaque block characters for extra detail

ascii-progress-bar.ts

// Example for 30.7% and length = 14: ████░─────────
// (to use this in JS, remove the `: type` annotations on line 9)

/**
 * Generates an ASCII progress bar with the given percentage and max length - uses opaque characters for extra detail
 * @param percentage A number from 0 to 100
 * @param barLength The length of the progress bar in characters
 */
function generateAsciiProgressBar(percentage: number, barLength: number) {
  const fullBlock = "█";
  const threeQuarterBlock = "▓";
  const halfBlock = "▒";
  const quarterBlock = "░";
  const emptyBlock = "─";
  
  if(percentage === 100)
    return fullBlock.repeat(barLength);

  const filledLength = Math.floor((percentage / 100) * barLength);
  const remainingPercentage = percentage / 10 * barLength - filledLength;

  let lastBlock = "";
  if(remainingPercentage >= 0.75)
    lastBlock = threeQuarterBlock;
  else if(remainingPercentage >= 0.5)
    lastBlock = halfBlock;
  else if (remainingPercentage >= 0.25)
    lastBlock = quarterBlock;

  const filledBar = fullBlock.repeat(filledLength);
  const emptyBar = emptyBlock.repeat(barLength - filledLength - (lastBlock ? 1 : 0));

  return `${filledBar}${lastBlock}${emptyBar}`;
}