path-prefix

#!/usr/bin/env node
// converts relative file paths at the beginning of each input line to absolute file paths
const path = require('path');
const fs = require('fs');
const rl = require('readline');

const REMOVE_COLORS = /[\u001b\u009b][[()#;?]*(?:[0-9]{1,4}(?:;[0-9]{0,4})*)?[0-9A-ORZcf-nqry=><]/g;

const dir = process.argv[2];
if (!dir) {
  throw new Error(`usage: path-prefix DIR`);
}

const reldir = path.relative(process.cwd(), dir);

const ifc = rl.createInterface(process.stdin);
ifc.on('line', line => {
  line = line.toString();
  const [ relative, ...rest ] = line.split(':');
  const rel = relative.replace(REMOVE_COLORS, '');
  const absolute = path.join(dir, rel);
  if (relative && fs.existsSync(absolute)) {
    process.stdout.write(path.join(reldir, rel) + ':' + rest.join(':') + '\n');
  } else {
    process.stdout.write(line + '\n');
  }
});

process.stdin.resume();

function exists(p) {
  try {
    fs.readFileSync(p);
    return true;
  } catch (e) {
    return false;
  }
}