Using gulp/node, how can I convert this JSON file into a YML file?

Starting file: config.json

{
  ":hello_world": "Test",
  ":foo_bar": [
    "One.js",
    "Two.txt",
  ]
}

Desired output: config.yml

:hello_world: Test 
:foo_bar:
- One.js
- Two.txt

You can use js-yaml, which seems to be the most widely used / adopted, and also is officially recommended by yaml.org

npm i js-yaml

Then you can read in the json file, parse with safeLoad, and then serialize with safeDump like this:

const { promises: fs } = require("fs")
const yaml = require('js-yaml');

(async function main() {

    try {

        let configJson = await fs.readFile("./config.json", "utf-8")
        let doc = yaml.safeLoad(configJson)
        let configYaml = yaml.safeDump(doc)
        await fs.writeFile("./config.yaml", configYaml, "utf-8")


    } catch (error) {
        console.log(error)
    }

})()

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