When I was reading the code, I see `parent` is not used in `_getComments` function.
so it make me confused why we delivery the `parent` in those functions.
If I'm wrong, please correct me.
* Add sourcemap examples for identifiers in code generator.
* Generate sourcemaps with exact mappings for identifiers, even if leading/trailing tokens also use that location.
* Fix OOB string character access in Printer#_maybeAddParen.
The `_maybeAddParen` method of the `Printer` class does
```js
const chaPost = str[i + 1]
```
without checking that `i + 1` is still within the bounds of `str`. It
seems like this triggers fairly often that the `str[i + 1]` access is
out of bounds. The first out of bounds access will turn the KeyedLoadIC
(in case of V8) into *MEGAMORPHIC* state, which is significantly slower
for strings (there's a fix in flight for V8 to mitigate the cost a bit
in that case). Even worse than that, the out of bounds access also
pollutes the later comparisons, namely
```js
chaPost === "/"
```
and
```js
chaPost === "*"
```
which are now no longer monomorphic on strings, since `chaPost` was
sometimes `undefined`.
This is a non-breaking performance fix, which improves babel execution
on the [web-tooling-benchmark](github.com/v8/web-tooling-benchmark)
workload by around 6-9%.
* Restructure and optimize the code a bit.
This reverts the former fix done in #5743 and always requeues
BlockStatements when they get created.
This also fixes a bug in babel-generator which would indent code
even though no comments are present.
* Remove parens around break and continue
Fixes#5742
* Fix space in doc comment
* Add some tests
* Remove newlines within CommentBlock
* Prevent newline before/after label
* Remove reference to node
* Check for label within startTerminatorless
* Print block instead of single line comment
* Clean up
* Remove whitespace generation and rely on default printing
Changes to printing:
* Add newline after last empty SwitchCase
* Add newlines around block comments if they are non-flow comments or contain newlines
* Fix a few more fixtures
