When comparing Pure.js vs FLAVE, the Slant community recommends FLAVE for most people. In the question“What are the best JavaScript templating engines?” FLAVE is ranked 26th while Pure.js is ranked 28th. The most important reason people chose FLAVE is:
Syntax Highlighting extensions for Atom and VSCODE
Ranked in these QuestionsQuestion Ranking
Pros
Pro Automatically extends JavaScript libraries available
If a Javascript library is available in the page when it's loaded, Pure will automatically extend it to use it inside the templates.
Pro Syntax Highlighting
Syntax Highlighting extensions for Atom and VSCODE
Pro JavaScript allowed in views
Pro Helper functions
Can write pure JavaScript helper functions to include in the view file.
Pro Multiple Templates in a single file
Optionally encapsulate views within a class as well as have as many view as you want.
Pro Not white space sensitive
Cons

Con Injection not explicit in template
Looking at the template, we cannot see where content will be injected. Instead, all we see are empty tags.

Con Not enough separation
The controller knows too much about the template.
Con Not many reasources outside the official documentation
PureJS is not very popular and it's not used by many. Because of this, there are not many guides or tutorials out there for Pure.js other than the official documentation.
Con Limited support and testing
Con No data binding
Flave only generates HTML.
