How do you measure size impact of a Kotlin depende...

# javascript

[shaktiman_droid]

How do you measure size impact of a Kotlin dependency on Kotlin/JS library release executable?

• One option is to build a JS executable via jsBrowserDistribution where we get a fat .js file.
Here is the output for this for my sample project

shared.js => 122KB
shared.js.map => 49KB

• Another option is to ship library as an NPM module. For example @Big Chungus’s plugin task `packJsNpmPublication`provides output like this for same sample project

npm notice === Tarball Contents === 
npm notice 316.8kB Kmp_Library-shared.js    
npm notice 117B    package.json             
npm notice 71.7kB  Kmp_Library-shared.js.map
npm notice 715B    Kmp_Library-shared.d.ts  
npm notice === Tarball Details === 
npm notice name:          shared                                  
npm notice version:       0.1.0                                   
npm notice filename:      shared-0.1.0.tgz                        
npm notice package size:  74.5 kB                                 
npm notice unpacked size: 389.3 kB

# Which number to believe from both options?

Now for example if I want to add kotlinx.datetime dependency in my project

I want to measure how much size impact it would do to my library user.

[Big Chungus]

The fat js file in most cases. Although some js libraries ship non js resources as well, in which case packed js publication is a better representation.

[shaktiman_droid]

@Big Chungus but if someone is shipping an NPM module (without any non js resources) then what does above sizes implicate that are shown as result of ``packJsNpmPublication` command ?

Or we need to every time go back to jsBrowserDistribution just to measure the accurate size?

[Big Chungus]

packJsNpmPublication depends on jsProductionExecutable and adds some metadata to it (like package.json, bundledDependencies, shrinkwrap.json). 99% of the time I personally would look at jsProductionExecutable output when comparing sizes.

[shaktiman_droid]

but that (output of jsProductionExecutable) would be unminified size right? For minified I guess we would still look at jsBrowserDistribution output size?

[Big Chungus]

No, production executable is already minified. jsCompileKotlin is one producing unminified output

[Big Chungus]

jsBrowserDistribution just collects your resources and js output

[shaktiman_droid]

but then shouldn't jsBrowserDistribution and jsProductionExecutable sizes match closely?

I get this output from jsProductionExecutable size of the shared.js in screenshot is 1.6MB but the size of fat .js file i get via jsBrowserDistribution is 800KB.

[Big Chungus]

Hmm, you might be onto something here. Not sure what's going on tbh.

[shaktiman_droid]

Hmm. It's fresh library with one method for testing so hopefully nothing wrong on my side. But yeah thanks for the help. I'll keep looking

[Big Chungus]

Initial size overhead for just using kotlin.js is quite substantial. I think the sizes you currently have are to be expected.

[shaktiman_droid]

Yeah makes sense. I was more confused from size mismatch/gap of around 800KB between jsProductionExecutable and jsBrowserDistribution outputs

[Big Chungus]

I think one is post dce, while another is post dce + post webpack

[shaktiman_droid]

Interesting