- We don't need a list of bindings to check if an identifier is unresolved.
- Checking if an identifier is unresolved is now one CPU instruction.
- Previously it was one hashmap operation.
- This PR also improves performance, by removing the hashmaps mentioned above.
- We now check if there's pending inlining before remapping variables.
- We now use ad-hoc type for remapping.
- We now inline before remapping to prevent interference with inlining.
swc_ecma_transforms_optimization:
- `expr_simplifier`: Track more changes.
swc_ecma_minifier:
- Analyze after applying the pure optimizer.
- Preserve access to a variable not in scope.
- `compress`: Remove string literal if it was not a directive.
- `pure/collapse_vars`: Merge vars declared in the first statement into one with initializers if `collapse_vars` and `join_vars` are enabled.
- `unused`: Use `usage_count` instead of `ref_count`.
- `unused`: Fix dropping rule for member expressions.
- `unused`: Fix dropping rule for declarations.
- `hoist_props`: Preserve exported items.
