Update relative imports in JS files to be absolute based on current path

update.py

import os
import re
import sys

ROOT_DIR = 'project-name'
PATTERN = re.compile(
    """(?P<prefix>.*from *['"])"""
    """(?P<path>\..*)"""
    """(?P<suffix>['"].*)"""
)


def replace_line(file_path, line):
    if not PATTERN.match(line):
        return line
    old_import_path = PATTERN.match(line).group('path')
    new_import_path = os.path.relpath(
        os.path.join(
            ROOT_DIR,
            os.path.dirname(file_path),
            old_import_path,
        )
    )
    return re.sub(
        PATTERN,
        r'\g<prefix>{}\g<suffix>'.format(new_import_path),
        line
    )


# usage: python update.py path/to/file.js
# Updates all relative imports in file.js to be absolute from current path
if __name__ == '__main__':
    file_path = sys.argv[1]

    with open(file_path) as in_file:
        old_lines = in_file.readlines()

    with open(file_path, 'w') as out_file:
        for line in old_lines:
            out_file.write(replace_line(file_path, line))