feat: avoid empty strings in the result

[tianenpang]

Description

Avoiding empty strings in the result to get a cleaner DOM.

Additional context

DOM example with empty result.

Before

<div class>...</div>

After

<div>...</div>

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What is the purpose of this pull request?

• [ ] Bug fix
• [x] New Feature
• [ ] Documentation update
• [x] Other

Before submitting the PR, please make sure you do the following

• [x] Read the Contributing Guidelines.
• [x] Follow the Style Guide.
• [x] Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• [x] Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).