replace references

replacer.js

const data = {
    "app": {
        "TITLE": "DoITnow",
        "PGAAS": "PostgreSQL - [app:TITLE]",
        "DB": "Database"
    },
    "postgres": {
        "TITLE": "[app:PGAAS] Database",
        "DESC": "This is [postgres:TITLE] Management consol in [app:TITLE]"
    }
}

function parser(data) {
    return JSON.parse(JSON.stringify(data), (key, value) => {
        if (typeof value === 'string') {
            return replacer(value, data);
        }
        return value;
    });
}

function replacer(value, data) {
    const reg = /\[([\D\_].*?):([\D\_].*?)]/gi;
    return value.replace(reg, (full, ns, nsKey) => {
        let keyValue = data[ns][nsKey];
        if (reg.test(keyValue)) {
            keyValue = replacer(keyValue, data);
        }
        return keyValue;
    })
}

const resp = parser(data);
console.log(resp);