relative-require.js

/**
 * Update relative `require`s in Node.js to use the minimal number of `../` path
 * pieces.
 *
 * Usage:
 *
 * ```shell
 * node relative-require.js path/to/my/file.js
 * ```
 */
const fs = require('fs')
const path = require('path')

const filename = path.join(process.cwd(), process.argv[process.argv.length - 1])
const contents = fs.readFileSync(filename, 'utf8')
const requires = new Set()
const pattern = /require\s*\(\s*(".*"|'.*')\s*\)/g
let mappedContents = contents
let result

/**
 * `pattern` is stateful. Use `RegExp#exec` to iterate through the matches and
 * get the first capture group.
 *
 * {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/exec}
 */
while (result = pattern.exec(contents)) {
  // Store `require(...)`s in a `Set` to prevent duplicate entries
  requires.add(result[1].slice(1, result[1].length - 1))
}

for (const r of requires.values()) {
  if (r[0] === '.') {
    mappedContents = mappedContents.replace(
      new RegExp(r, 'g'),
      path.relative(
        filename,
        path.resolve(path.dirname(filename), r)
      )
    )
  }
}

console.log(mappedContents)