SheetJS ad47cb433c Math.LOG2E precision issue + new demos [ci skip]

- swift + jsc
- java + rhino
- XMLHttpRequest and friends

2017-09-05 01:34:30 -04:00

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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);

duktape and skookum

Duktape is an embeddable JS engine written in C. The amalgamation makes integration extremely simple! Duktape understands the source code and can process binary strings out the box, but does not provide I/O or other standard library features.

To demonstrate compatibility with duktape, this demo uses the JS runtime from Skookum JS. Built upon the duktape engine, it adds a simple I/O interface to enable reading from files.

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