fix(html/minifier)/(ecma/minifier): bug with mangling

[alexander-akait]

Description:

Here two things:

• FIXED: bug when we don't apply compressor for script node
• FIXED: bug with topLevel for Program::Script and keep top level stuff by default not mangled
• FIXED: better default options for JS optimization

I have

<script>
 var topLevel = function test() {
            let foo = "bar";

            if (foo) {
                foo += "baz";
            }

            console.log(foo);
        };
</script>

For options I use: swc_ecma_minifier::option::MinifyOptions::default()

After minification I have:

<script>var topLevel=function test(){let foo="bar";if(foo){foo+="baz"}console.log(foo)}</script>

Yes, we keep topLevel, but foo is not mangling

Also if you use

swc_ecma_minifier::option::MinifyOptions {
                    compress: Some(swc_ecma_minifier::option::CompressOptions::default()),
                    mangle: Some(swc_ecma_minifier::option::MangleOptions {
                        top_level: false,
                        ..Default::default()
                    }),
                    ..Default::default()
                }

You will get (only for swc_ecma_ast::Program::Script, but if I changed it on swc_ecma_ast::Program::Module everything is fine):

<script>var o=function o(){let o="bar";if(o){o+="baz"}console.log(o)}</script>

i.e. top_level is not respected

BREAKING CHANGE:

No

Related issue (if exists):

No

[alexander-akait]

Here another bug with printing comments - space between /* Should mangle top level stuff */ and var o, we can should avoid it, because it increases size of bundle (I think this bug happens everywhere with comments), I will fix it in another PR

[kdy1]

Thanks!

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swc-bump:

• swc_ecma_minifier