aureooms/rejuvenate

export default function update(options) {
    return subroutine({overwrite: true, create: false, ...options});
}

async function subroutine({read, write, edit, overwrite, create}) {
    let original;
    try {
        original = await read();
        if (!overwrite) throw new Error('file exists');
    } catch (error) {
        if (error.code !== 'ENOENT' || !create) throw error;
    }

    const edited = await edit(original);
    await write(edited);
}