The spec was updated ( https://tc39.es/proposal-nullish-coalescing/ ) with the following two changes:
- ?? has lower precedence than ||. (previously equal)
- ?? cannot immediately contain, or be contained within, an && or || operation. (parens are now required)
The safe way to upgrade is to run prettier with just this change so that parenthesis are properly added. Then to upgrade the parser (only flow supports the new precendence in the next release, babel hasn't been updated yet) in prettier so that the new precedence is being used. Failure to do so will result in parse errors because of missing parenthesis so we will not have silent errors.
There was only 44 callsites mixing || and ?? in a confusing way in the Facebook codebase so it shouldn't be a huge deal in practice.
* Fix support for node 4 (#1988)
* Fix website on iOS Safari (#1970)
Formatting change:
* Position JSX whitespace (`{" "}`) at the end of lines (#1964)
Lots of small fixes, mainly for TypeScript.
If you put a space, `{loose: true}` is going to parse them as word + paren instead of func. It doesn't impact correctness and i'm not really sure how to clean the ast, so let's just make the test pass. I haven't seen this anywhere in real code.
This is working on the flow parser but not babylon
```js
echo 'class C<T> { submit<T>() { } }' | ./bin/prettier.js --stdin
class C<T> {
submit<T>() {}
}
```
If there you are opting in for double quote but there's a string with a double quote in it, it's better to swap to a single quote to avoid having too many `\`. Note that if there are both single and double quotes in the string, we should use the default string instead.
Fixes#139
This is working on the flow parser but not babylon
```js
echo 'function f(...flags: Array<boolean>) {}' | ./bin/prettier.js --stdin
function f(...flags: Array<boolean>) {}
```
This is a very handy way of playing out with prettier without having to install it. People have already been using it actively in the issues. Putting it directly inside of the repo would be better than on mine.
- This brings in the flow test suite that contains a ton of JavaScript parsing edge cases
- This creates snapshot tests using the pretty printer for all of them
- If uncomment `RUN_AST_TESTS` line in `tests/run_specs.js`, it checks ast(pretty_print(x)) == ast(x). Right now, "178 failed, 197 passed, 375 of 377 total". So half of the tests are not passing, most of them are crashes and many of the rest are subtle issues.
Christopher Chedeau