Fixes the next button

[IshaanPota]

Types of changes

• [x] Bugfix (change which fixes an issue)
• [ ] New feature (change which adds functionality)
• [ ] Refactor (change which changes the codebase without affecting its external behavior)
• [ ] Non-breaking change (fix or feature that would causes existing functionality to work as expected)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Purpose

Makes sure the next button does not light up when there are no more posts

Approach

The nextIsValid() function only returns true if there are posts left

Learning

Testing

Screenshot(s)

Checklist

• [ x] My branch follows the branch naming scheme of UCLA Radio, and can merge into master without error.
• [ ] My code follows the code style of this project, and I have linted it to confirm this.
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [ ] My change requires a change to the documentation and I have updated the documentation accordingly.
• [ ] All new and existing tests passed.

Link to Issue

https://github.com/uclaradio/uclaradio.com/issues/298

Platform

Operating System:
Node Version:

Further Comments

[tanzeelak]

I think this broke something in pagination: If I put an empty input in pagination, it should reset to 1 and go back to the first page. I checked tanzeela/blog-cleanup and it still does that. In this fix, it shows up like this:

[tanzeelak]

There's another bug introduced: If I search a post, e.g. "joji", and try to change pagination, it shouldn't let me go to a nonexistent page. I checked with tanzeela/blog-cleanup, and it remains at "1" when I put i page that's too large. On this PR, it tries to go to the page and the joji post disappears.