The current output of
```js
[...a, ...b]
```
is
```js
[...a, , ...b]
```
because flow parses it as
```
ArrayExpression(SpreadExpression, null, SpreadExpression)
```
This is a bug in the flow parser. Until it gets fixed, we can workaround it by deleting the `null` after a `SpreadExpression`.
* Remove +1 from newline detection
All the changes are related to spurious `;`. Sometimes the logic is more correct, sometimes less. Since `;` are going to be removed after the first save, I don't think it matters that much.
* Handle inconsistent `end` node locations when looking for newlines
I copy and pasted the code for arrays which doesn't have this problem. Would be nice to come up with an abstraction for a list of stuff separated by commas. It happens a lot of time and right now it's duplicated everywhere.
Fixes#255
According to @mroch, "Flow is using CESU-8, not UTF-8. http://www.unicode.org/reports/tr26/ ". While this is being fixed in flow, we can easily work around it inside of prettier. The downside of this approach is that we can't convert those strings to single or double quotes anymore.
```js
for (;;);
function f() {}
```
The `;` was dropped meaning that the line right after was executed within the for loop which is not correct.
I tried to return `;` but it looks like
```js
for (;;)
;
```
which looks super weird so I ended up printing `{}` which looks like
```js
for (;;) {}
```
The current implementation with `JSON.stringify()` is clever but unfortunately generates incorrect JavaScript. Using `jsesc` seems like a better and safer option. https://github.com/mathiasbynens/jsesc It doesn't have any dependencies and is pretty small.
I opted for escaping all the non ascii characters, so we don't display emojis anymore. I don't think that the world is ready yet for having random unicode characters inside of source files, there still are so many parts of the toolchain that breaks with them. If we want to revert back on this decision, there's a `minimal` option on jsesc which only escapes values that need to in order to generate valid JavaScript file (assuming the encoding of the file is set to utf8).
Also, while working on React Native, we've seen that there is an optimization inside of jsc for js files that are all ascii: it doesn't do a copy for the conversion to ucs16.
Fixes#163
There's a handful of files inside of Nuclide that throw exceptions because an assertion is raised.
```
{ AssertionError: ']' === '`'
at fixTemplateLiteral (/Users/vjeux/random/prettier/src/util.js:105:10)
at Object.util.fixFaultyLocations (/Users/vjeux/random/prettier/src/util.js:45:5)
at getSortedChildNodes (/Users/vjeux/random/prettier/src/comments.js:25:8)
at getSortedChildNodes (/Users/vjeux/random/prettier/src/comments.js:61:5)
at decorateComment (/Users/vjeux/random/prettier/src/comments.js:71:20)
at decorateComment (/Users/vjeux/random/prettier/src/comments.js:85:7)
at decorateComment (/Users/vjeux/random/prettier/src/comments.js:85:7)
at decorateComment (/Users/vjeux/random/prettier/src/comments.js:85:7)
at decorateComment (/Users/vjeux/random/prettier/src/comments.js:85:7)
at /Users/vjeux/random/prettier/src/comments.js:129:5
```
When trying https://github.com/facebook/nuclide/blob/master/pkg/nuclide-task-runner/lib/main.js#L174
It throws in the fixTemplateLiteral method.
That method was added to fix https://github.com/benjamn/recast/issues/216 more than a year ago
```js
var x = {
y: () => Relay.QL`
query {
${foo},
field,
}
`
};
```
I've checked (and added a test) and it now parses and prints correctly without that method. So it should be safe to remove.
Babylon has a bug where it doesn't escape DirectiveLiteral properly. Except for `'use strict';`, this never happens in real world code, so let's put strings in a array in order to workaround this bug and have the same output on both parsers.
https://github.com/babel/babylon/issues/289
DeclareInterface (flow) and InterfaceDeclaration (babylon) are the same type so should behave the same way. I am using the same `declare` trick where I only add it if you are inside of a `declare module` block.
The search for an empty line incorrectly does +1 which happens to be skipping a `\n`, but in case of windows line endings it skips the `\r` but sees a `\n` afterwards and incorrectly assumes that it is a empty line.
This doesn't change the behavior of doing +1 when there's not a line ending. Making it correct actually triggers a bunch of changes, where half of them are better and half of them regressions. So I'm going to send another pull request to fix that case.
When looking into adding a test, I realized that the logic was inside of bin/prettier.js and therefore only applying to the cli. Moving it to index.js and adding a test so that it's more robust :)
James Long
