@uppy/utils/lib/truncateString.js

Shared utility functions for Uppy Core and plugins maintained by the Uppy team.

/**
 * Truncates a string to the given number of chars (maxLength) by inserting '...' in the middle of that string.
 * Partially taken from https://stackoverflow.com/a/5723274/3192470.
 */
const separator = '...';
export default function truncateString(string, maxLength) {
  // Return the empty string if maxLength is zero
  if (maxLength === 0) return '';
  // Return original string if it's already shorter than maxLength
  if (string.length <= maxLength) return string;
  // Return truncated substring appended of the ellipsis char if string can't be meaningfully truncated
  if (maxLength <= separator.length + 1) return `${string.slice(0, maxLength - 1)}…`;
  const charsToShow = maxLength - separator.length;
  const frontChars = Math.ceil(charsToShow / 2);
  const backChars = Math.floor(charsToShow / 2);
  return string.slice(0, frontChars) + separator + string.slice(-backChars);
}