customAttrCollapse doesn't respect conservativeCollapse

[xReeQz]

In our angular.js based app we have attributes with long expressions which we sometimes spread over multiple lines like this:

repeat="role in modal.roles |
        filter: {displayName: $select.search}
        track by role.id"

Earlier we used minimize to minify HTML and that stuff would be collapsed correctly into:

repeat="role in modal.roles | filter: {displayName: $select.search} track by role.id"

Now after switching to webpack + html-loader we noticed that such attributes are not processed at all by default. customAttrCollapse + conservativeCollapse looked like exactly what we need, however it turned out that they don't work together. Is there a way to work around that?

[DanielRuf]

Hi @xReeQz,

can you provide a full example code for the html-minifier-terser so we have a testcase and the options that you use?

https://github.com/terser/html-minifier-terser/blob/v5.1.1/src/htmlminifier.js#L327

[xReeQz]

@DanielRuf here's an HTML sample:

<ui-select-choices 
    repeat="status in segment.statuses |
            filter: {displayName: $select.search}
            track by status.id"
>
  <span class="tu-match" 
        ng-bind-html="status.displayName | 
                      highlight: $select.search"
  ></span>
</ui-select-choices>

The options I use are:

{
  caseSensitive: true,
  collapseWhitespace: true,
  conservativeCollapse: true,
  keepClosingSlash: true,
  minifyCSS: true,
  minifyJS: true,
  removeComments: true,
  removeRedundantAttributes: true,
  removeScriptTypeAttributes: true,
  removeStyleLinkTypeAttributes: true,
  customAttrCollapse: /(ng-class|messages|repeat)/
}

[ybaws]

We have a similar issue in an Angular project, where multiple consecutive spaces get removed from our customAttrCollapse attributes/directives despite having conservativeCollapse: true in our options.

i.e.

alias="
  foo           as bar,
  bar           as foo,
  reallyLongFoo as bar
"

becomes

alias="fooas bar, baras foo, reallyLongFoo as bar"

changing https://github.com/terser/html-minifier-terser/blob/v5.1.1/src/htmlminifier.js#L328 to be

attrValue = trimWhitespace(attrValue.replace(/\n+|\r+/g, '').replace(/\s{2,}/g, options.conservativeCollapse ? ' ' : ''));

fixes our issue, but I'm not sure of the reasoning behind the \s{2,} part of the regex in the first place as to whether this is a reasonable fix or not?

[DanielRuf]

Can you test if this would result in a green CI build? You can provide a PR and we can see then if there are any negative side-effects or not.