Ukraine's declaration parser example (part)

declaration_example.js

// link to declaration.json – https://public-api.nazk.gov.ua/v1/declaration/41462809-89e2-4ad9-a9c9-54bb258541df
// usage: node declaration_example.js

'use strict';

var fs = require('fs');

function init() {
    let file = fs.readFileSync('declaration.json');
    let json = JSON.parse(file);
    
    let declaration = new Declaration();
    declaration.fromJSON(json);
    console.log(`owners: ${declaration.data.family.members}`);
}

class CustomStringConvertible {
    toString() {
        var d = `[ ${this.constructor.name} `;
        Object.keys(this).forEach(el => d += `${el}="${this[el]}" `);
        return d+']';
    }
}

class Declaration {
    fromJSON(value) {
        this.id = value.id;
        this.createdDate = value.created_date;
        this.lastModifiedDate = value.lastmodified_date;
        this.serverInfo = value.server_info;
        
        if(value.data != null) {
            this.data = new DeclarationData();
            this.data.fromJSON(value.data);
        }
    }
}

class DeclarationData {
    buildPart(value, classs) {
        if(this.notExist(value)) return null;
        
        let o = new classs();
        o.fromJSON(value);
        return o;
    }
    
    fromJSON(value) {
        this.info = this.buildPart(value.step_0, Info);
        console.log(`info: ${this.info.toString()}`);
        
        this.owner = this.buildPart(value.step_1, Owner);
        console.log(`owner: ${this.owner}`);
        
        this.family = this.buildPart(value.step_2, Family);
        console.log(`family: ${this.family}`);
    }
    
    notExist(value) {
        return value == null || !Object.keys(value).length;
    }
}

class Info extends CustomStringConvertible {
    fromJSON(value) {
        this.declarationType = value.declarationType;
        // strict assign etc
    }
}

class Owner extends CustomStringConvertible {
    fromJSON(value) {
        for(var i in value) {
            this[i] = value[i];
        }
    }
}

class Family extends CustomStringConvertible {
    fromJSON(value) {
        this.members = [];
        for(var i in value) {
            this.members.push(new Member(i));
        }
        
        this.members.forEach(el => el.fromJSON(value[el.id]))
    }
}

class Member extends CustomStringConvertible {
    constructor(id) {
        super();
        
        this.id = id;
    }
    
    fromJSON(value) {
        for(var i in value) {
            this[i] = value[i];
        }
    }
}

init();