patchClasses synchronizes an element’s CSS classes with class data from old and new virtual nodes. It converts both values into class lists, computes additions and removals, then updates the element’s classList. section 8.2.5
patchClasses
patchClasses is a book-specific function that synchronizes an element's CSS classes with virtual-node class data.
How Build a Frontend Web Framework (From Scratch) covers it
- How deep it goes
- Implements normalization, array diffing, and DOM updates, while leaving broader element patching to patchElement().
- Examples
- Uses implementation listings showing class normalization, added-and-removed class calculation, and classList mutation.
- What it assumes
- Assumes virtual-node props, arraysDiff, classList, and blank-string filtering; patchElement supplies the old and new class values.
- What you can do after
- Build it from scratch by converting class values, diffing class arrays, and applying removals and additions to an element.
- How it connects
- Connects virtual nodes, patchElement, arraysDiff, classList, and CSS classes.
This explainer was generated by Manning's knowledge graph from the text of Build a Frontend Web Framework (From Scratch). The section links point to the parts of the book it draws on.