Benedikt Meurer ffe4301fe2 Fix property lookup on booleans in needsWhitespace. (#6584)
The code

```js
linesInfo && linesInfo[type]
```

performs a lot of dynamic lookups on the `Boolean.prototype`, as the
*ToBoolean* operation let's `true` pass for `linesInfo` (which might
itself be concerning that this can be a boolean). Instead of the
coercion, the code should properly check for valid objects via `typeof`
and strict equality with `null` comparison.

This is a non-breaking performance fix.
2017-10-28 20:16:48 -04:00
..