docs.sheetjs.com/docz/docs/03-demos/42-engines/06-goja.md

title	sidebar_label	pagination_prev	pagination_next
Sheets in Golang with Goja	Go + Goja	demos/bigdata/index	solutions/input

import current from '/version.js'; import CodeBlock from '@theme/CodeBlock';

Goja¹ is a pure Go implementation of ECMAScript 5.

SheetJS is a JavaScript library for reading and writing data from spreadsheets.

This demo uses Goja and SheetJS to read and write spreadsheets. We'll explore how to load SheetJS in the Goja engine, exchange binary data with a Go program and process spreadsheets and structured data.

The "Complete Example" section makes a command-line tool for reading arbitrary workbooks and writing data to XLSB workbooks.

Integration Details

The SheetJS Standalone scripts can be parsed and evaluated in a Goja context.

Initialize Goja

Goja does not provide a global variable. It can be created in one line:

/* initialize */
vm := goja.New()

/* goja does not expose a standard "global" by default */
// highlight-next-line
v, err := vm.RunString("var global = (function(){ return this; }).call(null);")

Load SheetJS Scripts

The shim and main libraries can be loaded by reading the scripts from the file system and evaluating in the Goja context:

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) }
}

// ...
  safe_run_file(vm, "shim.min.js")
  safe_run_file(vm, "xlsx.full.min.js")

To confirm the library is loaded, XLSX.version can be inspected:

  /* get version string */
  v, err := vm.RunString("XLSX.version")
  fmt.Printf("SheetJS library version %s\n", v)

Reading Files

Files can be read into []byte:

/* read file */
data, _ := ioutil.ReadFile("sheetjs.xlsx")

[]byte should be converted to an ArrayBuffer from Go:

/* load into engine */
vm.Set("buf", vm.ToValue(vm.NewArrayBuffer(data)))

/* parse */
wb, _ = vm.RunString("wb = XLSX.read(buf, {type:'buffer'});")

Writing Files

"base64" strings can be passed from the JS context to Go code:

/* write to Base64 string */
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)

Complete Example

:::note Tested Deployments

This demo was tested in the following deployments:

Architecture	Git Commit	Go version	Date
darwin-x64	79f3a7e	1.23.3	2024-12-17
darwin-arm	ccbae20	1.22.3	2024-05-23
win11-x64	79f3a7e	1.23.4	2024-12-20
win11-arm	ccbae20	1.22.3	2024-05-25
linux-x64	e401ed4	1.22.1	2024-03-21
linux-arm	ccbae20	1.19.8	2024-05-25

At the time of writing, Goja did not have proper version numbers. Versions are identified by Git commit hashes.

:::

0. Create a module and install dependencies:

mkdir SheetGoja
cd SheetGoja
go mod init SheetGoja
go get github.com/dop251/goja

1. Download the SheetJS Standalone script, shim script and test file. Move all three files to the project directory:

• xlsx.full.min.js
• shim.min.js
• pres.numbers

{\ curl -LO https://cdn.sheetjs.com/xlsx-${current}/package/dist/shim.min.js curl -LO https://cdn.sheetjs.com/xlsx-${current}/package/dist/xlsx.full.min.js curl -LO https://docs.sheetjs.com/pres.numbers}

2. Download SheetGoja.go:

curl -LO https://docs.sheetjs.com/goja/SheetGoja.go

3. Build the standalone SheetGoja binary:

go build SheetGoja.go

4. Run the demo:

./SheetGoja 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.

---

1. The project does not have a website. The library is hosted on GitHub. ↩︎