Convert flat structures to deeply nested hierarchical data in node.js. Transform flat objects array representations to array of nested objects.
Basic usage example:
> npm install build-hierarchy -S
const HierarchyBuilder = require('build-hierarchy');
//Optionally required to view result.
const fs = require('fs');
const util = require('util');
/*
Taking input an array of flat structure
and returning hierarichal data as an output.
example :
input : [continent, country, state, city]
output : coninent -> country -> state -> city
*/
//Input flat structure.
const input = [
{
"Continent_ID": 1,
"Continent": "Asia",
"Country_ID": 101,
"Country": "India",
"State_ID": 1001,
"State": "Gujrat",
"City_ID": 10001,
"City": "Surat"
},
{
"Continent_ID": 1,
"Continent": "Asia",
"Country_ID": 101,
"Country": "India",
"State_ID": 1001,
"State": "Gujrat",
"City_ID": 10002,
"City": "Rajkot"
},
{
"Continent_ID": 1,
"Continent": "Asia",
"Country_ID": 101,
"Country": "India",
"State_ID": 1002,
"State": "Haryana",
"City_ID": 10003,
"City": "Gurugram"
},
{
"Continent_ID": 1,
"Continent": "Asia",
"Country_ID": 101,
"Country": "India",
"State_ID": 1002,
"State": "Haryana",
"City_ID": 10004,
"City": "Panipat"
},
{
"Continent_ID": 1,
"Continent": "Asia",
"Country_ID": 102,
"Country": "Thailand",
"State_ID": 1003,
"State": "Chiang Mai",
"City_ID": 10005,
"City": "Doi Saket"
},
{
"Continent_ID": 1,
"Continent": "Asia",
"Country_ID": 102,
"Country": "Thailand",
"State_ID": 1003,
"State": "Chiang Mai",
"City_ID": 10006,
"City": "Chom Thong"
},
{
"Continent_ID": 1,
"Continent": "Asia",
"Country_ID": 102,
"Country": "Thailand",
"State_ID": 1004,
"State": "Chiang Rai",
"City_ID": 10007,
"City": "Mae Suai"
},
{
"Continent_ID": 1,
"Continent": "Asia",
"Country_ID": 102,
"Country": "Thailand",
"State_ID": 1004,
"State": "Chiang Rai",
"City_ID": 10008,
"City": "Phan"
},
{
"Continent_ID": 2,
"Continent": "Africa",
"Country_ID": 107,
"Country": "South Africa",
"State_ID": 1005,
"State": "Northern Cape",
"City_ID": 10009,
"City": "Kimberley"
},
{
"Continent_ID": 2,
"Continent": "Africa",
"Country_ID": 107,
"Country": "South Africa",
"State_ID": 1005,
"State": "Northern Cape",
"City_ID": 10010,
"City": "Sutherland"
},
{
"Continent_ID": 2,
"Continent": "Africa",
"Country_ID": 107,
"Country": "South Africa",
"State_ID": 1006,
"State": "Eastern Cape",
"City_ID": 10011,
"City": "Stormsrivier"
},
{
"Continent_ID": 2,
"Continent": "Africa",
"Country_ID": 107,
"Country": "South Africa",
"State_ID": 1006,
"State": "Eastern Cape",
"City_ID": 10012,
"City": "Hogsback"
},
{
"Continent_ID": 3,
"Continent": "North America",
"Country_ID": 112,
"Country": "Canada",
"State_ID": 1007,
"State": "Ontario",
"City_ID": 10013,
"City": "Toronto"
},
{
"Continent_ID": 3,
"Continent": "North America",
"Country_ID": 112,
"Country": "Canada",
"State_ID": 1007,
"State": "Ontario",
"City_ID": 10014,
"City": "Ottawa"
},
{
"Continent_ID": 3,
"Continent": "North America",
"Country_ID": 112,
"Country": "Canada",
"State_ID": 1008,
"State": "Quebec",
"City_ID": 10015,
"City": "Montreal"
},
{
"Continent_ID": 3,
"Continent": "North America",
"Country_ID": 112,
"Country": "Canada",
"State_ID": 1008,
"State": "Quebec",
"City_ID": 10016,
"City": "Sherbrooke"
}
]
//Defining levels and properties to be used.
const levels = [
{
"level": 1,
"groupByKeys": ["Continent_ID"], //can be grouped by multiple properties.
"entities": [
{
"id": 1,
"name": "Continent",
"properties": {
"Continent_ID": "id", //property name alias.
"Continent": "name"
}
}
]
},
{
"level": 2,
"groupByKeys": [
"Country_ID"
],
"entities": [
{
"id": 1,
"name": "Country",
"properties": {
"Country_ID": "id",
"Country": "name"
}
}
]
},
{
"level": 3,
"groupByKeys": [
"State_ID"
],
"entities": [
{
"id": 1,
"name": "State",
"properties": {
"State_ID": "id",
"State": "state"
}
}
]
},
{
"level": 4,
"groupByKeys": ["City_ID"],
"entities": [
{
"id": 1,
"name": "City",
"properties": {
"City_ID": "id",
"City": "name"
}
}
]
}
];
const builder = new HierarchyBuilder();
const resultset = builder.buildHierarchy(input, levels);
//Using util.inspect method to see depply nested data.
console.log(util.inspect(resultset, { showHidden: false, depth: null, colors: true }))
//To view better logging resultset to a JSON file.
fs.writeFile("resultset.json", JSON.stringify(resultset), err => {
if (err) throw err;
console.log("Done writing resultset.json");
});
//Output :
/*
[
{
"id": 1,
"name": "Asia",
"children": [
{
"id": 101,
"name": "India",
"children": [
{
"id": 1001,
"state": "Gujrat",
"children": [
{
"id": 10001,
"name": "Surat",
"children": []
},
{
"id": 10002,
"name": "Rajkot",
"children": []
}
]
},
{
"id": 1002,
"state": "Haryana",
"children": [
{
"id": 10003,
"name": "Gurugram",
"children": []
},
{
"id": 10004,
"name": "Panipat",
"children": []
}
]
}
]
},
{
"id": 102,
"name": "Thailand",
"children": [
{
"id": 1003,
"state": "Chiang Mai",
"children": [
{
"id": 10005,
"name": "Doi Saket",
"children": []
},
{
"id": 10006,
"name": "Chom Thong",
"children": []
}
]
},
{
"id": 1004,
"state": "Chiang Rai",
"children": [
{
"id": 10007,
"name": "Mae Suai",
"children": []
},
{
"id": 10008,
"name": "Phan",
"children": []
}
]
}
]
}
]
},
{
"id": 2,
"name": "Africa",
"children": [
{
"id": 107,
"name": "South Africa",
"children": [
{
"id": 1005,
"state": "Northern Cape",
"children": [
{
"id": 10009,
"name": "Kimberley",
"children": []
},
{
"id": 10010,
"name": "Sutherland",
"children": []
}
]
},
{
"id": 1006,
"state": "Eastern Cape",
"children": [
{
"id": 10011,
"name": "Stormsrivier",
"children": []
},
{
"id": 10012,
"name": "Hogsback",
"children": []
}
]
}
]
}
]
},
{
"id": 3,
"name": "North America",
"children": [
{
"id": 112,
"name": "Canada",
"children": [
{
"id": 1007,
"state": "Ontario",
"children": [
{
"id": 10013,
"name": "Toronto",
"children": []
},
{
"id": 10014,
"name": "Ottawa",
"children": []
}
]
},
{
"id": 1008,
"state": "Quebec",
"children": [
{
"id": 10015,
"name": "Montreal",
"children": []
},
{
"id": 10016,
"name": "Sherbrooke",
"children": []
}
]
}
]
}
]
}
]
*/- lodash & node.js module.
- Ayush Pratap - Initial work - AyushPratap
[MIT License] © Ayush Pratap