function common(paths, sep = SEP) {
  const [first = "", ...remaining] = paths;
  if (first === "" || remaining.length === 0) {
    return first.substring(0, first.lastIndexOf(sep) + 1);
  }
  const parts = first.split(sep);
  let endOfPrefix = parts.length;
  for (const path of remaining) {
    const compare = path.split(sep);
    for (let i = 0; i < endOfPrefix; i++) {
      if (compare[i] !== parts[i]) {
        endOfPrefix = i;
      }
    }
    if (endOfPrefix === 0) {
      return "";
    }
  }
  const prefix = parts.slice(0, endOfPrefix).join(sep);
  return prefix.endsWith(sep) ? prefix : `${prefix}${sep}`;
}
/** Determines the common path from a set of paths, using an optional separator,
 * which defaults to the OS default separator.
 *
 *       import { common } from "https://deno.land/std/path/mod.ts";
 *       const p = common([
 *         "./deno/std/path/mod.ts",
 *         "./deno/std/fs/mod.ts",
 *       ]);
 *       console.log(p); // "./deno/std/"
 *
 */
Determines the common path from a set of paths, using an optional separator,
which defaults to the OS default separator.


Determines the common path from a set of paths using an optional separator which defaults to the OS default separator .
function common(paths, sep = SEP) {
  const [first = "", ...remaining] = paths;
  if (first === "" || remaining.length === 0) {
    return first.substring(0, first.lastIndexOf(sep) + 1);
  }
  const parts = first.split(sep);
  let endOfPrefix = parts.length;
  for (const path of remaining) {
    const compare = path.split(sep);
    for (let i = 0; i < endOfPrefix; i++) {
      if (compare[i] !== parts[i]) {
        endOfPrefix = i;
      }
    }
    if (endOfPrefix === 0) {
      return "";
    }
  }
  const prefix = parts.slice(0, endOfPrefix).join(sep);
  return prefix.endsWith(sep) ? prefix : `${prefix}${sep}`;
}
function common ( paths , sep = SEP ) { const [ first = "" , ... remaining ] = paths ; if ( first === "" || remaining . length === 0 ) { return first . substring ( 0 , first . lastIndexOf ( sep ) + 1 ) ; } const parts = first . split ( sep ) ; let endOfPrefix = parts . length ; for ( const path of remaining ) { const compare = path . split ( sep ) ; for ( let i = 0 ; i < endOfPrefix ; i ++ ) { if ( compare [ i ] !== parts [ i ] ) { endOfPrefix = i ; } } if ( endOfPrefix === 0 ) { return "" ; } } const prefix = parts . slice ( 0 , endOfPrefix ) . join ( sep ) ; return prefix . endsWith ( sep ) ? prefix : ` ${ prefix } ${ sep } ` ; }
Determines the common path from a set of paths, using an optional separator,
 which defaults to the OS default separator.
Determines the common path from a set of paths using an optional separator which defaults to the OS default separator .