Multiple Key Based Json Grouping

Question

I have a Json structure as shown below

[ { "category_id": "C1", "category_name": "C1_Name", "item_id": "C1_I1", "item_name": "C1_I1_Name", "variant_id": "C1_I1_V1", "variant_name": "C1_I1_V1_ Name" }, { "category_id": "C1", "category_name": "C1_Name", "item_id": "C1_I1", "item_name": "C1_I1_Name", "variant_id": "C1_I1_V2", "variant_name": "C1_I1_V2_ Name" }, { "category_id": "C1", "category_name": "C1_Name", "item_id": "C1_I2", "item_name": "C1_I2_Name", "variant_id": "C1_I2_V1", "variant_name": "C1_I2_V1_ Name" }, { "category_id": "C1", "category_name": "C1_Name", "item_id": "C1_I2", "item_name": "C1_I2_Name", "variant_id": "C1_I2_V2", "variant_name": "C1_I2_V2_ Name" }, { "category_id": "C2", "category_name": "C2_Name", "item_id": "C2_I1", "item_name": "C2_I1_Name", "variant_id": "C2_I1_V1", "variant_name": "C2_I1_V1_ Name" } ] 

I would like to group the Json level to N 'in javascript, for example by passing a list of keys. For example, giving category_id, item_id and variant_id, I expect the following answer:

 [ { "category_id": "C1", "category_name": "C1_Name", "item": [ { "item_id": "C1_I1", "item_name": "C1_I1_Name", "variant": [ { "variant_id": "C1_I1_V1", "variant_name": "C1_I1_V1_ Name" }, { "variant_id": "C1_I1_V2", "variant_name": "C1_I1_V2_ Name" } ] }, { "item_id": "C1_I2", "item_name": "C1_I2_Name", "variant": [ { "variant_id": "C1_I2_V1", "variant_name": "C1_I2_V1_ Name" }, { "variant_id": "C1_I2_V2", "variant_name": "C1_I2_V2_ Name" } ] } ] } ] 

Do you need help on how to do this?

I tried something like the following, but it groups together for one level. I would like it to be recursive.

 function groupBy(collection, property) { var i = 0, val, index, values = [], result = []; for (; i < collection.length; i++) { val = collection[i][property]; index = values.indexOf(val); if (index > -1) result[index].push(collection[i]); else { values.push(val); result.push([collection[i]]); } } return result; } 

Answer 1

Here is my solution to the problem (Javascript only):

 function getItemByKey(arr, key, value){ // here we look for existing group item in the result array return arr.reduce(function (prev, cur) { if (prev == null && cur[key] == value) { return cur; } return prev; }, null); } function checkPropForGroup(prop, key){ // here we check which columns should stay in the group, // and which should go down to group items. return prop == key || prop == key.replace("_id", "_name"); } function cloneSuperItem(src, key){ // create super item by copying only group related fields var item = {}; for (prop in src){ if (checkPropForGroup(prop, key)){ item[prop] = src[prop]; } } item[key+'_group'] = []; return item; } function cloneSubItem(src, key){ // create sub-item by copying all but group related fields var item = {}; for (prop in src){ if (!checkPropForGroup(prop, key)){ item[prop] = src[prop]; } } return item; } function groupArray(arr, args, lvl){ var key = args[lvl]; var result = []; arr.forEach(function (item, ind, a){ // find or create super item for group and then create sub item // and push it there var keyItem = getItemByKey(result, key, item[key]); if (!keyItem){ keyItem = cloneSuperItem(item, key); result.push(keyItem); } subItem = cloneSubItem(item, key); keyItem[key+'_group'].push(subItem); }); if (args[lvl+1]){ // recursively make grouping on lower level for (var i = 0; i < result.length; i++){ result[i][key+'_group'] = groupArray(result[i][key+'_group'], args, lvl + 1); } } return result; } function groupArrayMain(arr, keysArray){ // keys should be simply listed as parameters in order from top group to lower return JSON.stringify(groupArray(arr, arguments, 1),null,'\n') } var arr = [ { "category_id": "C1", "category_name": "C1_Name", "item_id": "C1_I1", "item_name": "C1_I1_Name", "variant_id": "C1_I1_V1", "variant_name": "C1_I1_V1_ Name" }, { "category_id": "C1", "category_name": "C1_Name", "item_id": "C1_I1", "item_name": "C1_I1_Name", "variant_id": "C1_I1_V2", "variant_name": "C1_I1_V2_ Name" }, { "category_id": "C1", "category_name": "C1_Name", "item_id": "C1_I2", "item_name": "C1_I2_Name", "variant_id": "C1_I2_V1", "variant_name": "C1_I2_V1_ Name" }, { "category_id": "C1", "category_name": "C1_Name", "item_id": "C1_I2", "item_name": "C1_I2_Name", "variant_id": "C1_I2_V2", "variant_name": "C1_I2_V2_ Name" }, { "category_id": "C2", "category_name": "C2_Name", "item_id": "C2_I1", "item_name": "C2_I1_Name", "variant_id": "C2_I1_V1", "variant_name": "C2_I1_V1_ Name" } ] groupArrayMain(arr, "category_id", "item_id", "variant_id") 

I also put this as jsfiddle