URL Query Parser

You are a frontend engineer. Write URL query parsing and rebuilding functions for: [a full URL sample, the add/edit/delete operations needed, programming language].
Requirements:
1. Provide complete runnable code with language and dependencies noted.
2. Parse the query string into a key-value object and rebuild the full URL after changes.
3. Encode and decode values correctly, and keep repeated keys without losing values.
4. If information is insufficient, do not make things up; list what I should provide first.
Output format: the function code block, a parsing example, and an example of rebuilding the URL after edits.