This happens:

![](VimAutoIndentJavascriptHtml_001.png)

That is:
```
          if( dur.match(/:/) ) {
                let xs = dur.split(":")
                if( xs.length > 3 ) return nan()
                if( xs.length == 3 ) {
                      let [ h, m, s ] = xs
                      h = parseInt(h)
                      m = parseInt(m)
                      s = parseFloat(s)
                      if( isNaN(h) || isNaN(m) || isNaN(s) ) return nan()
                      dur = s + 60 * m + 3600 * h
                    } else if( xs.length == 2 ) {
                      let [ m, s ] = xs
                      m = parseInt(m)
                      s = parseFloat(s)
                      if( isNaN(m) || isNaN(s) ) return nan()
                          dur = s + 60 * m 
                        } else {
                              return nan()
                            }
              } else {
                    dur = parseFloat(dur)
                    if( isNaN(dur) ) return nan()
                  }
```
where there are two extra right shifts after an open brace. I suspect that three different autoindent facilities are trying to indent, and are adding to each other.