docs.sheetjs.com/docz/docs/03-demos/31-engines.md

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---
title: JavaScript Engines
---
import current from '/version.js';
import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';
The most popular JavaScript engine is V8. Designed for embedding in software,
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it powers Chrome, NodeJS, UXP, Deno and many other platforms.
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There are many other JS engines with different design goals. Some are designed
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for low-power or low-memory environments. Others aim for interoperability with
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specific programming languages or environments. Typically they support ES3 and
are capable of running SheetJS code.
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## General Caveats
Common browser and NodeJS APIs are often missing from light-weight JS engines.
**Global**
Some engines do not provide `globalThis` or `global` or `window`. A `global`
variable can be exposed in one line that should be run in the JS engine:
```js
var global = (function(){ return this; }).call(null);
```
**Console**
Some engines do not provide a `console` object. `console.log` can be shimmed
using the engine functionality. For example, `hermes` provides `print()`:
```js
var console = { log: function(x) { print(x); } };
```
**Binary Data**
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Some engines do not provide easy ways to exchange binary data. For example, it
is common to pass null-terminated arrays, which would truncate XLSX, XLS, and
other exports. APIs that accept pointers without length should be avoided.
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Base64 strings are safe for passing between JS and native code, but they should
only be used when there is no safe way to pass `ArrayBuffer` or `Uint8Array`.
## Duktape
Duktape is an embeddable JS engine written in C. It has been ported to a number
of exotic architectures and operating systems.
**Reading data**
Duktape supports `Buffer` natively but should be sliced before processing:
```c
/* 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.slice(0, buf.length), {type:'buffer'});");
```
**Writing data**
`duk_get_buffer_data` can pull `Buffer` object data into the C code:
```c
/* write a workbook object to a C char array */
duk_eval_string(ctx, "XLSX.write(workbook, {type:'array', bookType:'xlsx'})");
duk_size_t sz;
char *buf = (char *)duk_get_buffer_data(ctx, -1, sz);
duk_pop(ctx);
```
<details><summary><b>Complete Example</b> (click to show)</summary>
:::note
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This demo was tested on Intel Mac (`darwin-x64`).
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:::
0) Download and extract the latest release (2.7.0 at the time of writing)
```bash
curl -LO https://duktape.org/duktape-2.7.0.tar.xz
tar -xJf duktape-2.7.0.tar.xz
mv duktape-2.7.0/src/*.{c,h} .
```
1) Download the standalone script, shim and test file:
<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js`}>shim.min.js</a></li>
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<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
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<li><a href="https://sheetjs.com/pres.numbers">pres.numbers</a></li>
</ul>
2) Save the following script to `sheetjs.duk.c`:
```c title="sheetjs.duk.c"
/* sheetjs (C) 2013-present SheetJS -- http://sheetjs.com */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "duktape.h"
#define FAIL_LOAD { \
duk_push_undefined(ctx); \
perror("Error in load_file"); \
return 1; \
}
static char *read_file(const char *filename, size_t *sz) {
FILE *f = fopen(filename, "rb");
if(!f) return NULL;
long fsize; { fseek(f, 0, SEEK_END); fsize = ftell(f); fseek(f, 0, SEEK_SET); }
char *buf = (char *)malloc(fsize * sizeof(char));
*sz = fread((void *) buf, 1, fsize, f);
fclose(f);
return buf;
}
static duk_int_t eval_file(duk_context *ctx, const char *filename) {
size_t len; char *buf = read_file(filename, &len);
if(!buf) FAIL_LOAD
duk_push_lstring(ctx, (const char *)buf, (duk_size_t)len);
duk_int_t retval = duk_peval(ctx);
duk_pop(ctx);
return retval;
}
static duk_int_t load_file(duk_context *ctx, const char *filename, const char *var) {
size_t len; char *buf = read_file(filename, &len);
if(!buf) FAIL_LOAD
duk_push_external_buffer(ctx);
duk_config_buffer(ctx, -1, buf, len);
duk_put_global_string(ctx, var);
return 0;
}
static duk_int_t save_file(duk_context *ctx, const char *filename, const char *var) {
duk_get_global_string(ctx, var);
duk_size_t sz;
char *buf = (char *)duk_get_buffer_data(ctx, -1, &sz);
if(!buf) return 1;
FILE *f = fopen(filename, "wb"); fwrite(buf, 1, sz, f); fclose(f);
return 0;
}
#define FAIL(cmd) { \
printf("error in %s: %s\n", cmd, duk_safe_to_string(ctx, -1)); \
duk_destroy_heap(ctx); \
return res; \
}
#define DOIT(cmd) duk_eval_string_noresult(ctx, cmd);
int main(int argc, char *argv[]) {
duk_int_t res = 0;
/* initialize */
duk_context *ctx = duk_create_heap_default();
/* duktape does not expose a standard "global" by default */
DOIT("var global = (function(){ return this; }).call(null);");
/* load library */
res = eval_file(ctx, "shim.min.js");
if(res != 0) FAIL("shim load")
res = eval_file(ctx, "xlsx.full.min.js");
if(res != 0) FAIL("library load")
/* get version string */
duk_eval_string(ctx, "XLSX.version");
printf("SheetJS library version %s\n", duk_get_string(ctx, -1));
duk_pop(ctx);
/* read file */
res = load_file(ctx, argv[1], "buf");
if(res != 0) FAIL("file load")
printf("Loaded file %s\n", argv[1]);
/* parse workbook */
DOIT("wb = XLSX.read(buf.slice(0, buf.length), {type:'buffer'});");
DOIT("ws = wb.Sheets[wb.SheetNames[0]]");
/* print CSV */
duk_eval_string(ctx, "XLSX.utils.sheet_to_csv(ws)");
printf("%s\n", duk_get_string(ctx, -1));
duk_pop(ctx);
/* write file */
#define WRITE_TYPE(BOOKTYPE) \
DOIT("newbuf = (XLSX.write(wb, {type:'array', bookType:'" BOOKTYPE "'}));");\
res = save_file(ctx, "sheetjsw." BOOKTYPE, "newbuf");\
if(res != 0) FAIL("save sheetjsw." BOOKTYPE)
WRITE_TYPE("xlsb")
/* cleanup */
duk_destroy_heap(ctx);
return res;
}
```
3) Compile standalone `sheetjs.duk` binary
```bash
gcc -std=c99 -Wall -osheetjs.duk sheetjs.duk.c duktape.c -lm
```
4) Run the demo:
```bash
./sheetjs.duk pres.numbers
```
If the program succeeded, the CSV contents will be printed to console and the
file `sheetjsw.xlsb` will be created. That file can be opened with Excel.
</details>
## Goja
Goja is a pure Go implementation of ECMAScript 5. It supports the standalone
scripts out of the box.
**Reading data**
Files can be read into `[]byte`:
```go
/* read file */
data, _ := ioutil.ReadFile("sheetjs.xlsx")
```
`[]byte` should be converted to an `ArrayBuffer` from Go:
```go
/* load into engine */
vm.Set("buf", vm.ToValue(vm.NewArrayBuffer(data)))
/* parse */
wb, _ = vm.RunString("wb = XLSX.read(buf, {type:'buffer'});")
```
**Writing data**
`"base64"` strings can be decoded in Go:
```go
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/* write to Base64 string */
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b64str, _ := vm.RunString("XLSX.write(wb, {type:'base64', bookType:'xlsx'})")
/* pull data back into Go and write to file */
buf, _ := base64.StdEncoding.DecodeString(b64str.String())
_ = ioutil.WriteFile("sheetjs.xlsx", buf, 0644)
```
<details><summary><b>Complete Example</b> (click to show)</summary>
0) Install Go
1) Create a `go.mod` file and install dependencies:
```bash
go mod init SheetGoja
go get github.com/dop251/goja
```
2) Download the standalone script and the shim:
<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js`}>shim.min.js</a></li>
</ul>
3) Save the following code to `SheetGoja.go`:
```go title="SheetGoja.go"
package main
import (
b64 "encoding/base64"
"fmt"
"os"
"io/ioutil"
"github.com/dop251/goja"
)
func safe_run_file(vm *goja.Runtime, file string) {
data, err := ioutil.ReadFile(file)
if err != nil { panic(err) }
src := string(data)
_, err = vm.RunString(src)
if err != nil { panic(err) }
}
func eval_string(vm *goja.Runtime, cmd string) goja.Value {
v, err := vm.RunString(cmd)
if err != nil { panic(err) }
return v
}
func write_type(vm *goja.Runtime, t string) {
b64str := eval_string(vm, "XLSX.write(wb, {type:'base64', bookType:'" + t + "'})")
buf, err := b64.StdEncoding.DecodeString(b64str.String());
if err != nil { panic(err) }
err = ioutil.WriteFile("sheetjsg." + t, buf, 0644)
if err != nil { panic(err) }
}
func main() {
vm := goja.New()
/* initialize */
eval_string(vm, "if(typeof global == 'undefined') global = (function(){ return this; }).call(null);")
/* load library */
safe_run_file(vm, "shim.min.js")
safe_run_file(vm, "xlsx.full.min.js")
/* get version string */
v := eval_string(vm, "XLSX.version")
fmt.Printf("SheetJS library version %s\n", v)
/* read file */
data, err := ioutil.ReadFile(os.Args[1])
if err != nil { panic(err) }
vm.Set("buf", vm.ToValue(vm.NewArrayBuffer(data)))
fmt.Printf("Loaded file %s\n", os.Args[1])
/* parse workbook */
eval_string(vm, "wb = XLSX.read(buf, {type:'buffer'});")
fmt.Printf("Parsed %s\n", os.Args[1])
eval_string(vm, "ws = wb.Sheets[wb.SheetNames[0]]")
fmt.Printf("Grabbed %s\n", os.Args[1])
/* print CSV */
csv := eval_string(vm, "XLSX.utils.sheet_to_csv(ws)")
fmt.Printf("%s\n", csv)
/* write file */
write_type(vm, "csv")
}
```
4) Build `SheetGoja`:
```bash
go build SheetGoja.go
```
For testing, download <https://sheetjs.com/pres.numbers> and run
```bash
./SheetGoja pres.numbers
```
This will print the contents as a CSV to screen AND write to `sheetjsg.csv`
</details>
## Hermes
Hermes is an embeddable JS engine for React Native. The library and binary
distributions include a command-line tool `hermes` for running JS scripts.
The simplest way to interact with the engine is to pass Base64 strings. The make
target builds a very simple payload with the data.
:::note
The official release includes the `hermes` standalone tool. While applications
should link against the official libraries, the standalone tool is useful for
verifying functionality.
:::
<details><summary><b>Complete Example</b> (click to show)</summary>
Due to limitations of the standalone binary, this demo will encode a test file
as a Base64 string and directly add it to an amalgamated script.
0) Install the `hermes` command line tool
1) Download the standalone script, shim, and test file:
<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js`}>shim.min.js</a></li>
<li><a href="https://sheetjs.com/pres.numbers">pres.numbers</a></li>
</ul>
2) Bundle the test file and create `payload.js`:
```bash
node -e "fs.writeFileSync('payload.js', 'var payload = \"' + fs.readFileSync('pres.numbers').toString('base64') + '\";')"
```
3) Create support scripts:
- `global.js` creates a `global` variable and defines a fake `console`:
```js title="global.js"
var global = (function(){ return this; }).call(null);
var console = { log: function(x) { print(x); } };
```
- `hermes.js` will call `XLSX.read` and `XLSX.utils.sheet_to_csv`:
```js title="hermes.js"
/* sheetjs (C) 2013-present SheetJS -- http://sheetjs.com */
var wb = XLSX.read(payload, {type:'base64'});
console.log(XLSX.utils.sheet_to_csv(wb.Sheets[wb.SheetNames[0]]));
```
4) Create the amalgamation `xlsx.hermes.js`:
```bash
cat global.js xlsx.full.min.js payload.js hermes.js > xlsx.hermes.js
```
The final script defines `global` before loading the standalone library. Once
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ready, it will read the bundled test data and print the contents as CSV.
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5) Run the script using the Hermes standalone binary:
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```bash
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hermes xlsx.hermes.js
```
</details>
## JavaScriptCore
:::warning Platform Limitations
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JavaScriptCore is primarily deployed in MacOS and iOS applications. There is
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some experimental support through the Bun runtime, but production applications
intending to support Windows / Linux / Android should try to embed V8.
:::
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iOS and MacOS ship with the JavaScriptCore framework for running JS code from
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Swift and Objective-C. Hybrid function invocation is tricky, but explicit data
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passing is straightforward. The demo shows a standalone Swift sample for MacOS.
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Binary strings can be passed back and forth using `String.Encoding.isoLatin1`.
**Reading data**
`String(contentsOf:encoding:)` reads from a path and returns an encoded string:
```swift
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/* read sheetjs.xls as Base64 string */
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let file_path = shared_dir.appendingPathComponent("sheetjs.xls");
let data: String! = try String(contentsOf: file_path, encoding: String.Encoding.isoLatin1);
```
This string can be loaded into the JS engine and processed:
```swift
/* load data in JSC */
context.setObject(data, forKeyedSubscript: "payload" as (NSCopying & NSObjectProtocol));
/* `payload` (the "forKeyedSubscript" parameter) is a binary string */
context.evaluateScript("var wb = XLSX.read(payload, {type:'binary'});");
```
**Writing data**
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When writing to binary string in JavaScriptCore, the result should be stored in
a variable and converted to string in Swift:
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```swift
/* write to binary string */
context.evaluateScript("var out = XLSX.write(wb, {type:'binary', bookType:'xlsx'})");
/* `out` from the script is a binary string that can be stringified in Swift */
let outvalue: JSValue! = context.objectForKeyedSubscript("out");
var out: String! = outvalue.toString();
```
`String#write(to:atomically:encoding)` writes the string to the specified path:
```swift
/* write to sheetjsw.xlsx */
let out_path = shared_dir.appendingPathComponent("sheetjsw.xlsx");
try? out.write(to: out_path, atomically: false, encoding: String.Encoding.isoLatin1);
```
The demo includes a sample `SheetJSCore` Wrapper class to simplify operations.
<details><summary><b>Complete Example</b> (click to show)</summary>
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:::caution This demo only runs on MacOS
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This example requires MacOS + Swift and will not work on Windows or Linux!
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:::
0) Ensure Xcode is installed
1) Download the standalone script, the shim and the test file:
<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js`}>shim.min.js</a></li>
<li><a href="https://sheetjs.com/pres.numbers">pres.numbers</a></li>
</ul>
2) Download the Swift scripts for the demo
- [`SheetJSCore.swift`](pathname:///swift/SheetJSCore.swift) Wrapper library
- [`main.swift`](pathname:///swift/main.swift) Command-line script
3) Build the `SheetJSwift` binary:
```bash
swiftc SheetJSCore.swift main.swift -o SheetJSwift
```
4) Test the program:
```bash
./SheetJSwift pres.numbers
```
If successful, a CSV will be printed to console. The script also tries to write
to `SheetJSwift.xlsx`. That file can be verified by opening in Excel / Numbers.
</details>
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## JerryScript
JerryScript is a lightweight JavaScript engine designed for use in low-memory
environments like microcontrollers. As part of the build suite, the project
generates a C library and a standalone CLI tool.
The simplest way to interact with the engine is to pass Base64 strings.
:::note
While applications should link against the official libraries, the standalone tool
is useful for verifying functionality.
:::
:::caution
This demo requires a much larger heap size than is normally used in JerryScript
deployments! In local testing, the following sizes were needed:
- 8192 (8M) for <https://sheetjs.com/pres.xlsx>
- 65536 (64M) for <https://sheetjs.com/pres.numbers>
This works on a Raspberry Pi.
:::
<details><summary><b>Complete Example</b> (click to show)</summary>
Due to limitations of the standalone binary, this demo will encode a test file
as a Base64 string and directly add it to an amalgamated script.
0) Build the library and command line tool with required options:
```bash
git clone --depth=1 https://github.com/jerryscript-project/jerryscript.git
cd jerryscript
python tools/build.py --error-messages=ON --logging=ON --mem-heap=8192 --cpointer-32bit=ON
```
1) Download the standalone script, shim, and test file:
<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js`}>shim.min.js</a></li>
<li><a href="https://sheetjs.com/pres.xlsx">pres.xlsx</a></li>
</ul>
2) Bundle the test file and create `payload.js`:
```bash
node -e "fs.writeFileSync('payload.js', 'var payload = \"' + fs.readFileSync('pres.xlsx').toString('base64') + '\";')"
```
3) Create support scripts:
- `global.js` creates a `global` variable and defines a fake `console`:
```js title="global.js"
var global = (function(){ return this; }).call(null);
var console = { log: function(x) { print(x); } };
```
- `jerry.js` will call `XLSX.read` and `XLSX.utils.sheet_to_csv`:
```js title="jerry.js"
/* sheetjs (C) 2013-present SheetJS -- http://sheetjs.com */
var wb = XLSX.read(payload, {type:'base64'});
console.log(XLSX.utils.sheet_to_csv(wb.Sheets[wb.SheetNames[0]]));
```
4) Create the amalgamation `xlsx.jerry.js`:
```bash
cat global.js xlsx.full.min.js payload.js jerry.js > xlsx.jerry.js
```
The final script defines `global` before loading the standalone library. Once
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ready, it will read the bundled test data and print the contents as CSV.
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5) Run the script using the `jerry` standalone binary:
```bash
build/bin/jerry xlsx.jerry.js; echo $?
```
</details>
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## QuickJS
QuickJS is an embeddable JS engine written in C. It provides a separate set of
functions for interacting with the filesystem and the global object. It can run
the standalone browser scripts.
<details><summary><b>Complete Example</b> (click to show)</summary>
0) Ensure `quickjs` command line utility is installed
1) Download the standalone script, the shim and the test file:
<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js`}>shim.min.js</a></li>
<li><a href="https://sheetjs.com/pres.numbers">pres.numbers</a></li>
</ul>
2) Save the following script to `SheetJSQuick.js`:
```js title="SheetJSQuick.js
/* sheetjs (C) 2013-present SheetJS -- http://sheetjs.com */
/* load XLSX */
import * as std from "std";
globalThis.global = globalThis;
std.loadScript("xlsx.full.min.js");
/* read contents of file */
var rh = std.open("pres.numbers", "rb");
rh.seek(0, std.SEEK_END);
var sz = rh.tell();
var ab = new ArrayBuffer(sz);
rh.seek();
rh.read(ab, 0, sz);
rh.close();
/* parse file */
var wb = XLSX.read(ab, {type: 'array'});
/* write array */
var out = XLSX.write(wb, {type: 'array'});
/* write contents to file */
var wh = std.open("SheetJSQuick.xlsx", "wb");
wh.write(out, 0, out.byteLength);
wh.close();
```
3) Test the program:
```bash
quickjs SheetJSQuick.js
```
If successful, the script will generate `SheetJSQuick.xlsx`.
</details>
## Rhino
Rhino is an ES3+ engine 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 turned off:
```java
Context context = Context.enter();
context.setOptimizationLevel(-1);
```
<details><summary><b>Complete Example</b> (click to show)</summary>
0) Download the appropriate Rhino build and rename to `rhino.jar`
1) Download [`SheetJSRhino.zip`](pathname:///rhino/SheetJSRhino.zip) and unzip
2) Save the following code to `SheetJSRhino.java`:
```java title="SheetJSRhino.java"
/* sheetjs (C) 2013-present SheetJS -- http://sheetjs.com */
/* vim: set ts=2: */
import com.sheetjs.SheetJS;
import com.sheetjs.SheetJSFile;
import com.sheetjs.SheetJSSheet;
public class SheetJSRhino {
public static void main(String args[]) throws Exception {
try {
SheetJS sjs = new SheetJS();
/* open file */
SheetJSFile xl = sjs.read_file(args[0]);
/* get sheetnames */
String[] sheetnames = xl.get_sheet_names();
System.err.println(sheetnames[0]);
/* convert to CSV */
SheetJSSheet sheet = xl.get_sheet(0);
String csv = sheet.get_csv();
System.out.println(csv);
} catch(Exception e) {
throw e;
} finally {
SheetJS.close();
}
}
}
```
3) Assemble `SheetJS.jar` from the demo code:
```bash
javac -cp .:rhino.jar SheetJSRhino.java
jar -cf SheetJS.jar SheetJSRhino.class com/sheetjs/*.class
```
4) Download <https://sheetjs.com/pres.xlsx> and test:
```bash
java -cp .:SheetJS.jar:rhino.jar SheetJSRhino pres.xlsx
```
</details>
## Legacy Engines
:::warning
These examples were written when the engines were maintained. New projects
should not use these engines. The demos are included for legacy deployments.
:::
### ChakraCore
:::caution
ChakraCore was an open source JavaScript engine released by Microsoft. It was a
fork of the Chakra engine that powered Internet Explorer. When Microsoft Edge
switched to become a fork of Chromium, Microsoft stopped providing support.
:::
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 interact with the engine is to pass Base64 strings. The make
target builds a very simple payload with the data.
:::note
The official release includes the `ch` standalone binary. While applications
should link against the official libraries, the standalone tool is useful for
verifying functionality.
:::
<details><summary><b>Complete Example</b> (click to show)</summary>
Due to limitations of the standalone binary, this demo will encode a test file
as a Base64 string and directly add it to an amalgamated script.
0) Download and extract the ChakraCore release ZIP. Copy the binary (`bin/ch`)
to your project folder.
1) Download the standalone script, shim, and test file:
<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js`}>shim.min.js</a></li>
<li><a href="https://sheetjs.com/pres.numbers">pres.numbers</a></li>
</ul>
2) Bundle the test file and create `payload.js`:
```bash
node -e "fs.writeFileSync('payload.js', 'var payload = \"' + fs.readFileSync('pres.numbers').toString('base64') + '\";')"
```
3) Create support scripts:
- `global.js` creates a `global` variable:
```js title="global.js"
var global = (function(){ return this; }).call(null);
```
- `chakra.js` will call `XLSX.read` and `XLSX.utils.sheet_to_csv`:
```js title="chakra.js"
/* sheetjs (C) 2013-present SheetJS -- http://sheetjs.com */
var wb = XLSX.read(payload, {type:'base64'});
console.log(XLSX.utils.sheet_to_csv(wb.Sheets[wb.SheetNames[0]]));
```
4) Create the amalgamation `xlsx.chakra.js`:
```bash
cat global.js xlsx.full.min.js payload.js chakra.js > xlsx.chakra.js
```
The final script defines `global` before loading the standalone library. Once
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ready, it will read the bundled test data and print the contents as CSV.
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5) Run the script using the ChakraCore standalone binary:
```
./ch xlsx.chakra.js
```
</details>
### Nashorn
:::caution
Nashorn shipped with Java 8. It was deprecated in Java 11 and was officially
removed in JDK 15. New Java applications should use [Rhino](#rhino).
:::
Nashorn ships with Java. It includes a command-line tool `jjs` for running JS
scripts. It is somewhat limited but does offer access to the full Java runtime.
The `load` function in `jjs` can load the minified source directly:
```js
var global = (function(){ return this; }).call(null);
load('xlsx.full.min.js');
```
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"`.
<details><summary><b>Complete Example</b> (click to show)</summary>
0) Ensure `jjs` is available on system path
1) Download the standalone script, the shim and the test file:
<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href={`https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js`}>shim.min.js</a></li>
<li><a href="https://sheetjs.com/pres.numbers">pres.numbers</a></li>
</ul>
2) Save the following script to `SheetJSNashorn.js`:
```js title="SheetJSNashorn.js"
/* sheetjs (C) 2013-present SheetJS -- http://sheetjs.com */
/* load module */
var global = (function(){ return this; }).call(null);
load('xlsx.full.min.js');
/* helper to convert byte array to plain JS array */
function b2a(b) {
var out = new Array(b.length);
for(var i = 0; i < out.length; i++) out[i] = (b[i] < 0 ? b[i] + 256 : b[i]);
return out;
}
function process_file(path) {
java.lang.System.out.println(path);
/* read file */
var path = java.nio.file.Paths.get(path);
var bytes = java.nio.file.Files.readAllBytes(path);
var u8a = b2a(bytes);
/* read data */
var wb = XLSX.read(u8a, {type:"array"});
/* get first worksheet as an array of arrays */
var ws = wb.Sheets[wb.SheetNames[0]];
var js = XLSX.utils.sheet_to_json(ws, {header:1});
/* print out every line */
js.forEach(function(l) { java.lang.System.out.println(JSON.stringify(l)); });
}
process_file('pres.numbers');
```
3) Test the script:
```bash
jjs SheetJSNashorn.js
```
It will print out the first worksheet contents.
</details>