transformer_example.js

let tree = parser.parse('{"c": ["a", "b",2]}')

// Object-based transformer
let OT = lark.Transformer.fromObj({
	array:  (args) => args,
	pair:   (args) => args,
	number: ([x])  => parseInt(x.value),
	string: ([x])  => x.value.slice(1, -1),
	object: (entries) => Object.fromEntries(entries)
})

// Class-based transformer
class CT extends lark.Transformer {
	array(args) {
		return args
	}
	pair(args) {
		return args
	}
	string([x]) {
		return x.value.slice(1, -1) 
	}
	number([x]) {
		return parseInt(x.value)
	}
	object(entries) {
		return Object.fromEntries(entries)
	}
}

let json1 = OT.transform(tree)
let json2 = new CT().transform(tree)