Read Data Field Action

GitHub Action to extract content from data files. How it works:

• Provide a file path to some data (supports JSON, JSON5, JSONC, YAML and TOML)
• Provide a field to index the data, like version, author.name or keywords[0]
• Read the output with ${{ steps.<step-id>.outputs.result }}

Jump to:

• inputs
• field syntax
• outputs
• examples

Installation

Add this action to your workflow by referencing it in your .github/workflows/*.yml file:

- uses: seaofvoices/read-data-field-action@v1
  id: <enter-an-id-to-refer-to>
  with:
    file: package.json
    field: version

Inputs

Input	Description	Required
file	Path to the data file to read	Yes
field	Dot-separated field path to extract (e.g., scripts.build, database.host)	Yes

Field Syntax

The field input uses dot-notation syntax to traverse nested data structures. You can access object properties, array elements.

• use . to index by a property name
• use [<integer>] to index an array. Replace <integer> with a valid 0-based array index, e.g. [0] to index the first element.

Field Examples

Here are a few examples of field paths that can be used. Note that the examples are using JSON data, but these are valid for any supported data format.

Field Path	Data	Result
version	{"version": "1.0.0"}	"1.0.0"
author.name	{"author": {"name": "John"}}	"John"
scripts.build	{"scripts": {"build": "rollup"}}	"rollup"
keywords[0]	{"keywords": ["json", "parser"]}	"json"
keywords[1]	{"keywords": ["json", "parser"]}	"parser"
authors[0].name	{"authors": [{"name": "Alice"}, {"name": "Bob"}]}	"Alice"
config.servers[1].host	{"config": {"servers": [{"host": "dev"}, {"host": "prod"}]}}	"prod"

Escaping Special Characters

Escape special characters using backslashes \.

character	usage	data example	field example	result
.	Index a property that contains a .	{ "luau-lsp.platform.type": "roblox" }	luau-lsp\.platform\.type	roblox
\	Index a property that contains a \	{ "a\b": false }	a\\b	false
[	Index a property that contains a [	{ "[dev]": "localhost" }	\[dev]	localhost

Outputs

The action produces 2 output values. Look at the examples to see how to read them.

Output	Description
result	The extracted data in its original type
result_json	The extracted data encoded as JSON string

Examples

Extract version from package.json

- name: Read package version
  id: package-info
  uses: seaofvoices/read-data-field-action@v1
  with:
    file: package.json
    field: version

- name: Use the version
  run: echo "Package version is ${{ steps.package-info.outputs.result }}"

Extract nested configuration values

- name: Read build script
  id: build-script
  uses: seaofvoices/read-data-field-action@v1
  with:
    file: package.json
    field: scripts.build

- name: Read nested YAML configuration
  id: config
  uses: seaofvoices/read-data-field-action@v1
  with:
    file: config.yaml
    field: database.host

Working with TOML files

- name: Read Cargo package name
  id: cargo-info
  uses: seaofvoices/read-data-field-action@v1
  with:
    file: Cargo.toml
    field: package.name

Supported File Formats

The action supports multiple data formats and uses intelligent parsing:

• JSON (.json) - Standard JSON format
• JSON5 (.json5) - JSON5 with comments and trailing commas
• JSONC (.json) - JSON with comments (falls back if standard JSON parsing fails)
• YAML (.yml, .yaml) - YAML format
• TOML (.toml) - TOML format

The parser automatically detects the format based on file extension and tries all available parsers.

License

This project is available under the MIT license. See LICENSE.txt for details.