function compile(obj, op) {

    if (obj.regolaPerCollegamento)

        return obj.regolaPerCollegamento.map(p => JSON.stringify(p)).join(op)

    let res = []

    for (let [op, val] of Object.entries(obj)) {

        if (op === 'and')

            res.push(compile(val, ' && '))

        if (op === 'or')

            res.push(compile(val, ' || '))

        if (op === 'not')

            res.push('not ' + compile(val, ' '))

    }

    if (res.length === 1)

        return res[0]

    return '(' + res.join(op) + ')'

}

//

let json = {

    "or": {

        "and": {

            "regolaPerCollegamento": [

                {

                    "tipoCollegamentoEsistente": 115,

                    "quantita": "NESSUNO"

                },

                {

                    "tipoCollegamentoEsistente": 118,

                    "quantita": "NESSUNO"

                }

            ]

        },

        "or": {

            "regolaPerCollegamento": [

                {

                    "tipoCollegamento": 115,

                    "minimo": 1

                },

                {

                    "tipoCollegamento": 118,

                    "minimo": 1

                }

            ]

        }

    }

}

b = compile(json, ' ')

console.log(b)

interface Rule { 

whatever

}

interface Node

{

    op: string

    args: Array <Node | Rule>

}

//

let ast = {

    op: 'or',

    args: [

        {

            op: 'and',

            args: [

                { "tipoCollegamentoEsistente": 115, "quantita": "NESSUNO" },

                { "tipoCollegamentoEsistente": 118, "quantita": "NESSUNO" }

            ]

        },

        {

            op: 'or',

            args: [

                { "tipoCollegamento": 115, "minimo": 1 },

                { "tipoCollegamento": 118, "minimo": 1 }

            ]

        }

    ]

}