hcl2-json-parser

HCL v2 parser for JS

This is a HCL version 2 parser for JavaScript, there are several other JS parsers for HCL but none that support the newer HCL v2 syntax.

It wraps the very helpful tmccombs/hcl2json and calls the convert package in order to parse HCL input strings to JSON strings. The Go code in parser.go is converted to JS using GopherJS

This is an updated version of hcl2-parser. The original library is no longer maintained, and did not return errors to the user. This version returns a Promise that is rejected when an error (e.g. a syntax error) is returned while parsing.

TypeScript definitions are included

Reference

The module exports the following functions:

// Returns the parsed JSON String, or rejects with the error.
function parseToString(input: string): Promise<string>
// Returns the parsed JSON string converted to an object with JSON.parse(),
// or rejects with the error.
function parseToObject(input: string): Promise<AnyJson>

Usage

Install as normal with NPM

npm install hcl2-json-parser

Importing into your project

// Good old fashioned Node.js CommonJS require
const hcl = require("hcl2-json-parser")

// Import with ES6 or TypeScript
import * as hcl = from "hcl2-json-parser"

Simple example of usage

const hcl = require("hcl2-json-parser")

const hclString = `
# Create a resource group
variable "azureRegion" {
  type = string
  default = "uksouth"
}
resource "azurerm_resource_group" "example" {
  name     = "example-resources"
  location = var.azureRegion
}
`

// Parse into a JSON string
stringResult = await hcl.parseToString(hclString)
console.log(stringResult)

// Parse into an object
objectResult = await hcl.parseToObject(hclString)
console.log(objectResult.resource.azurerm_resource_group)

try {
  result = await hcl.parseToObject("invalid hcl!!!");
} catch (e) {
  // `e` will contain the error thrown by the underlying github.com/tmccombs/hcl2json library.
}