yourWaifu / snapit-js

Snapit JS

Fast and memory efficient JavaScript runtime for front-ends by using ahead of time compiling.

Build

Note: only building on Windows is supported

1. Download hermes version rn/0.74-stable (github.com)
2. Build it but don't follow their build instructions because they are incorrect Watch the build output, you'll want to know where the library files are outputted for later. Look for text like "Build files have been written to:" and "Linking CXX static library".

Afterwards, find the following library files in the build folder, and copy all of them to snapit-js/external/

library	Windows
hermesVMRuntime	lib\VM\hermesVMRuntime.lib
hermesAST	lib\AST\hermesAST.lib
hermesHBCBackend	lib\BCGen\HBC\hermesHBCBackend.lib
hermesBackend	lib\BCGen\hermesBackend.lib
hermesOptimizer	lib\hermesOptimizer.lib
hermesFrontend	lib\hermesFrontend.lib
hermesParser	lib\Parser\hermesParser.lib
hermesSupport	lib\Support\hermesSupport.lib
dtoa	external\dtoa\dtoa.lib
hermesSourceMap	lib\SourceMap\hermesSourceMap.lib
hermesADT	lib\ADT\hermesADT.lib
hermesInst	lib\Inst\hermesInst.lib
hermesFrontEndDefs	lib\FrontEndDefs\hermesFrontEndDefs.lib
hermesRegex	lib\Regex\hermesRegex.lib
hermesPlatform	lib\Platform\hermesPlatform.lib
hermesInternalBytecode	lib\InternalBytecode\hermesInternalBytecode.lib
hermesPublic	public\hermes\Public\hermesPublic.lib
hermesInstrumentation	lib\VM\Instrumentation\hermesInstrumentation.lib
hermesPlatformUnicode	lib\Platform\Unicode\hermesPlatformUnicode.lib
LLVHSupport	external\llvh\lib\Support\LLVHSupport.lib
LLVHDemangle	external\llvh\lib\Demangle\LLVHDemangle.lib
hermesc	bin\hermesc .exe and .pdb

find the following directories and copy them to snapit-js/external/

All OSs	Windows
{hermes build output}\external\llvh\include\ -> include
include\ -> include
external\llvh\include\ -> include
external\llvh\gen\include\ -> include
public\hermes\ -> include\hermes
external\flowparser\include\ -> include
external\icu_decls\ -> include

change current directory to snapit-js

cd snapit-js

run cargo build

cargo build

run example

cargo run test.hbc

Use

build JS code

.\external\hermesc .\path\to\code.js -emit-binary -out path\to\output.hbc

run JS code

cargo run path\to\output.hbc

Performance trade-offs

Since all code that runs needs to go to the compiler first, all eval or dynamic imports will need to be known ahead of time or otherwise have to wait for the compiler before the module can run.