sheetjs/demos/altjs

Other JS Engines and Deployments

There are many JS engines and deployments outside of web browsers. NodeJS is the most popular deployment, but there are many others for special use cases. Some optimize for low overhead and others optimize for ease of embedding within other applications. Since it was designed for ES3 engines, the library can be used in those settings! This demo tries to demonstrate a few alternative deployments.

Some engines provide no default global object. To create a global reference:

var global = (function(){ return this; }).call(null);

Swift + JavaScriptCore

iOS and OSX ship with the JavaScriptCore framework, enabling easy JS access from Swift and Objective-C. Hybrid function invocation is tricky, but explicit data passing is straightforward.

Binary strings can be passed back and forth using String.Encoding.ascii.

Nashorn

Nashorn ships with Java 8. It includes a command-line tool jjs for running JS scripts. It is somewhat limited but does offer access to the full Java runtime.

jjs does not provide a CommonJS require implementation. This demo uses a shim and manually requires the library.

The Java nio API provides the Files.readAllBytes method to read a file into a byte array. To use in XLSX.read, the demo copies the bytes into a plain JS array and calls XLSX.read with type "array".

Rhino

Rhino is an ES3+ engine written in Java. The SheetJSRhino class and com.sheetjs package show a complete JAR deployment, including the full XLSX source.

Due to code generation errors, optimization must be disabled:

Context context = Context.enter();
context.setOptimizationLevel(-1);

ChakraCore

ChakraCore is an embeddable JS engine written in C++. The library and binary distributions include a command-line tool chakra for running JS scripts.

The simplest way to interop with the engine is to pass Base64 strings. The make target builds a very simple payload with the data.

Duktape

Duktape is an embeddable JS engine written in C. The amalgamation makes integration extremely simple! It supports Buffer natively:

/* parse a C char array as a workbook object */
duk_push_external_buffer(ctx);
duk_config_buffer(ctx, -1, buf, len);
duk_put_global_string(ctx, "buf");
duk_eval_string_noresult("workbook = XLSX.read(buf, {type:'buffer'});");

/* write a workbook object to a C char array */
duk_eval_string(ctx, "XLSX.write(workbook, {type:'buffer', bookType:'xlsx'})");
duk_size_t sz;
char *buf = (char *)duk_get_buffer_data(ctx, -1, sz);
duk_pop(ctx);