JS dynamically access & delete nested object property [duplicate] - javascript

This is the sample json:
{
"search": {
"facets": {
"author": [
],
"language": [
{
"value": "nep",
"count": 3
},
{
"value": "urd",
"count": 1
}
],
"source": [
{
"value": "West Bengal State Council of Vocational Education & Training",
"count": 175
}
],
"type": [
{
"value": "text",
"count": 175
}
],
}
}
There are several ways to delete key search.facets.source:
delete search.facets.source
delete jsobObj['search']['facets']['source']
var jsonKey = 'source';
JSON.parse(angular.toJson(jsonObj), function (key, value) {
if (key != jsonKey)
return value;
});
Above 1 & 2 are not dynamic, and 3 is one of the way but not a proper way. Because if source is present in another node then it will not work. Please anybody can tell me how to delete it dynamically in any kind of nested key. Because we can not generate sequence of array dynamically in above 2.

Assuming you're starting from this:
let path = 'search.facets.source';
Then the logic is simple: find the search.facets object, then delete obj['source'] on it.
Step one, divide the path into the initial path and trailing property name:
let keys = path.split('.');
let prop = keys.pop();
Find the facets object in your object:
let parent = keys.reduce((obj, key) => obj[key], jsonObj);
Delete the property:
delete parent[prop];

I have found out another solution, it is very easy.
var jsonKey = 'search.facets.source';
eval('delete jsonObj.' + jsonKey + ';');

Related

How to convert JSON string having multiple rows to single row using javascript function

I have an output of REST API in following JSON format:
I need to convert the format to flat format so it can be passed as input to another API call.
{
"result": {
"data": [
{
"data": 2.824315071105957,
"dateTime": "2019-09-10T11:32:05.220Z",
"device": { "id": "b3" },
"diagnostic": { "id": "DiagnosticAccelerationForwardBrakingId" },
"controller": "ControllerNoneId",
"version": "00000000000363b0",
"id": "a5UyPzhknSC-N2wtLBph3BA"
},
{
"data": 0,
"dateTime": "2019-09-10T11:32:05.220Z",
"device": { "id": "b3" },
"diagnostic": { "id": "DiagnosticAccelerationSideToSideId" },
"controller": "ControllerNoneId",
"version": "00000000000363b1",
"id": "a5UyPzhknSC-N2wtLBph3BQ"
},
// ... 1000's of rows like this
]
}
}
I need to convert it in below format using a java-script
Desired format:
{"result":{ "data":[{"id":"b3","dateTime":"2019-09- 10T11:32:05.220Z","DiagnosticAccelerationSideToSideId":0,"DiagnosticAccelerationForwardBrakingId ":2.824315071105957},...
The rows needs to be merged with primary key as combination of ID and dateTime attributes. Please note the diagnostic id value becomes key for the required format and data value is the value of the key.
Is there any way to convert this JSON to above flat format.
Need to convert JSON having many rows for single data entry to single row format. Need one java-script function that can accept a string of rows format and convert or merge it and return the string in desired format
function String mergeRows(String flatDataJSONString) {
...
}
If the items are ordered (meaning i and i+1 are merged) than iterate with jumps of i += 2;
If its not ordered or the amount of items to be merged can be > 2 you use an object with unique key composed of the id and date, and override its data whenever a record match this key:
function merger (jsonStr) {
// convert str to obj
const jsonObj = JSON.parse(jsonStr);
const dataObj = {};
for (let i = 0; i < jsonObj.result.length; i++) {
const item = jsonObj.result[i];
// use unique key to merge by
const itemUniqueKey = item.device.id + item.dateTime;
// take last value or create empty object if not exists
const existingItem = dataObj[itemUniqueKey] || {};
// add some logic to merge item with existingItem as you need
...
// set the result back to dataObj to be used on next merges
dataObj[itemUniqueKey] = [merge result of item and existing item];
}
// take dataObj values, you don't need the keys any more
const dataArr = Object.values(dataObj);
const finalResult = {
result: {
data: dataArr
}
}
// convert back to json
return JSON.stringify(finalResult);
}
As stated in the comment you want first to have a clean json definition in order to stringify it. Please get to the following definition of your JSON first:
const json = {
"result": [
{
"data": 2.824315071105957,
"dateTime": "2019-09-10T11:32:05.220Z",
"device": { "id": "b3" },
"diagnostic": { "id": "DiagnosticAccelerationForwardBrakingId" },
"controller": "ControllerNoneId",
"version": "00000000000363b0",
"id": "a5UyPzhknSC-N2wtLBph3BA"
},
{
"data": 0,
"dateTime": "2019-09-10T11:32:05.220Z",
"device": { "id": "b3" },
"diagnostic": { "id": "DiagnosticAccelerationSideToSideId" },
"controller": "ControllerNoneId",
"version": "00000000000363b1",
"id": "a5UyPzhknSC-N2wtLBph3BQ"
}]
};
and then you will be able to perform like hereafter :
JSON.stringify(json)
Hope this helps !

How to get all values of given specific keys (for e.g: name) without loop from json?

I want to fetch all the names and label from JSON without loop. Is there a way to fetch with any filter method?
"sections": [
{
"id": "62ee1779",
"name": "Drinks",
"items": [
{
"id": "1902b625",
"name": "Cold Brew",
"optionSets": [
{
"id": "45f2a845-c83b-49c2-90ae-a227dfb7c513",
"label": "Choose a size",
},
{
"id": "af171c34-4ca8-4374-82bf-a418396e375c",
"label": "Additional Toppings",
},
],
},
]
}
When you say "without loops" I take it as without For Loops. because any kind of traversal of arrays, let alone nested traversal, involve iterating.
You can use the reduce method to have it done for you internally and give you the format you need.
Try this :
const data = {
sections: [
{
id: "62ee1779",
name: "Drinks",
items: [
{
id: "1902b625",
name: "Cold Brew",
optionSets: [
{
id: "45f2a845-c83b-49c2-90ae-a227dfb7c513",
label: "Choose a size"
},
{
id: "af171c34-4ca8-4374-82bf-a418396e375c",
label: "Additional Toppings"
}
]
}
]
}
]
};
x = data.sections.reduce((acc, ele) => {
acc.push(ele.name);
otherName = ele.items.reduce((acc2, elem2) => {
acc2.push(elem2.name);
label = elem2.optionSets.reduce((acc3, elem3) => {
acc3.push(elem3.label);
return acc3;
}, []);
return acc2.concat(label);
}, []);
return acc.concat(otherName);
}, []);
console.log(x);
Go ahead and press run snippet to see if this matches your desired output.
For More on info reduce method
In the context of cJSON
yes, we can fetch the key value for any of the object.
1 - each key value is pointed by one of the objects. will simply fetch that object and from there will get the key value.
In the above case for
pre-requisition: root must contain the json format and root must be the cJSON pointer. if not we can define it and use cJSON_Parse() to parse the json.
1st name object is "sections" will use
cJSON *test = cJSON_GetObjectItem(root, "sections");
char *name1 = cJSON_GetObjectItem(test, "name" )->valuestring;
2nd name key value
cJSON *test2 = cJSON_GetObjectItem(test, "items");
char *name2 = cJSON_GetObjectItem(tes2, "name")->valuestring;
likewise, we can do for others as well to fetch the key value.

Combining values in nested objects with common properties

# Problem
Hello. I have a JSON response containing a varying amount of objects (a set of indicators), each containing a fixed set of other objects (geometries) that each contain properties (one of which is 'score').
I'm trying to gather these 'score' properties in order to later do stuff such as min/mean/max by geometry.
# Sample
Here's an example (keeping in mind there could be more than two indicators):
let data = [ {
{
"indicator": "A",
"geom": "1",
"score": 1
},
{
"indicator": "A",
"geom": "2",
"score": 2
} }, {
{
"indicator": "B",
"geom": "1",
"score": 3
},
{
"indicator": "B",
"geom": "2",
"score": 4
} } ]
# Expected result
The result I'm looking for would be something like this, with concatenated values originating from different sub-objects :
let expectedResult = {
{
"indicator": ["A", "B"],
"geom": "1",
"score": [1,3]
},
{
"indicator": ["A", "B],
"geom": "2",
"score": [2,4]
} }
# My (no good) solution
My current, ugly buggy solution is to create an array with all geom ids :
let id = data[0].map(obj => obj.geom);
Then get a complete list of all key-value :
let keyval;
data.map((indic) => { indic.map((geom) =>
{ keyval.push([car.geom, car.score])})});
And finally combine geom id var with values that have identical id (and slice off the redundant id) :
id.map((geom, idx) => {keyval.map((arr) => {
if (car === arr[0]) { id.push(geom, arr.splice(0,1)})
}
})
});
Would anyone know of a more elegant/efficient.. and more importantly working solution ? During my research saw a lot of Array.prototype.reduce(), but didn't figure out how to use it in such a nested configuration.
Thanks,
O.
Use Array#reduce to collect the values into a Map, then use Map#values, and the spread syntax to convert back to an array:
const data = [[{"indicator":"A","geom":"1","score":1},{"indicator":"A","geom":"2","score":2}],[{"indicator":"B","geom":"1","score":3},{"indicator":"B","geom":"2","score":4}]];
const result = [...[].concat(...data).reduce((map, o) => {
const item = map.get(o.geom) || { geom: o.geom, indicator: [], score: [] }; // get the item from the map, or create a new one
item.indicator.push(o.indicator);
item.score.push(o.score);
return map.set(o.geom, item); // set the item and return the map reference
}, new Map).values()]; // get the map values iterator, and use spread (...) to get an array
console.log(result);

replace multiple values in json/jsObject/string

I have a response from a web service and want to replace some values in the response with my custom values.
One way is to write a tree traverser and then check for the value and replace with my custom value
so the response is some what like this:
[
{
"name": "n1",
"value": "v1",
"children": [
{
"name": "n2",
"value": "v2"
}
]
},
{
"name": "n3",
"value": "v3"
}
]
now my custom map is like this
const map = {
"v1": "v11",
"v2": "v22",
"v3": "v33"
};
All I want is
[
{
"name": "n1",
"value": "v11",
"children": [
{
"name": "n2",
"value": "v22"
}
]
},
{
"name": "n3",
"value": "v33"
}
]
I was thinking if I could stringify my response and then replace values using a custom build regex from my map of values.
Will it be faster as compared to tree traverser?
If yes, how should I do that?
somewhat like this
originalString.replace(regexp, function (replacement))
The tree traversal is faster
Note that some things could be done more efficiently in the regex implementation but I still think there are some more bottlenecks to explain.
Why the regex is slow:
There are probably many more reasons why the regex is slower but I'll explain at least one significant reason:
When you're using regex to find and replace, you're using creating new strings every time and performing your matches every time. Regex expressions can be very expensive and my implementation isn't particularly cheap.
Why is the tree traversal faster:
In the tree traversal, I'm mutating the object directly. This doesn't require creating new string objects or any new objects at all. We're also not performing a full search on the whole string every time as well.
RESULTS
run the performance test below. The test using console.time to record how long it takes. See the the tree traversal is much faster.
function usingRegex(obj, map) {
return JSON.parse(Object.keys(map).map(oldValue => ({
oldValue,
newValue: map[oldValue]
})).reduce((json, {
oldValue,
newValue
}) => {
return json.replace(
new RegExp(`"value":"(${oldValue})"`),
() => `"value":"${newValue}"`
);
}, JSON.stringify(obj)));
}
function usingTree(obj, map) {
function traverse(children) {
for (let item of children) {
if (item && item.value) {
// get a value from a JS object is O(1)!
item.value = map[item.value];
}
if (item && item.children) {
traverse(item.children)
}
}
}
traverse(obj);
return obj; // mutates
}
const obj = JSON.parse(`[
{
"name": "n1",
"value": "v1",
"children": [
{
"name": "n2",
"value": "v2"
}
]
},
{
"name": "n3",
"value": "v3"
}
]`);
const map = {
"v1": "v11",
"v2": "v22",
"v3": "v33"
};
// show that each function is working first
console.log('== TEST THE FUNCTIONS ==');
console.log('usingRegex', usingRegex(obj, map));
console.log('usingTree', usingTree(obj, map));
const iterations = 10000; // ten thousand
console.log('== DO 10000 ITERATIONS ==');
console.time('regex implementation');
for (let i = 0; i < iterations; i += 1) {
usingRegex(obj, map);
}
console.timeEnd('regex implementation');
console.time('tree implementation');
for (let i = 0; i < iterations; i += 1) {
usingTree(obj, map);
}
console.timeEnd('tree implementation');
Will it be faster as compared to tree traverser?
I don't know. I think it would depend on the size of the input, and the size of the replacement map. You could run some tests at JSPerf.com.
If yes, how should I do that?
It's fairly easy to do with a regex-based string replacement if the values you are replacing don't need any special escaping or whatever. Something like this:
const input = [
{
"name": "n1",
"value": "v1",
"children": [
{
"name": "n2",
"value": "v2"
}
]
},
{
"name": "n3",
"value": "v3"
}
];
const map = {
"v1": "v11",
"v2": "v22",
"v3": "v33"
};
// create a regex that matches any of the map keys, adding ':' and quotes
// to be sure to match whole property values and not property names
const regex = new RegExp(':\\s*"(' + Object.keys(map).join('|') + ')"', 'g');
// NOTE: if you've received this data as JSON then do the replacement
// *before* parsing it, don't parse it then restringify it then reparse it.
const json = JSON.stringify(input);
const result = JSON.parse(
json.replace(regex, function(m, key) { return ': "' + map[key] + '"'; })
);
console.log(result);
definitely traverser go faster as string replace means travels against each characters in the final string as opposed to iterator that can skips no necessarily item.

JSON/JS Object accessing key when you don't know the name in Google Apps Script

I'm working with a response from the Webtrends API in Google apps script and I have a JSON/JS object that looks like this:
"data": [
{
"period": "Month",
"start_date": "2013-12",
"end_date": "2013-12",
"attributes": {},
"measures": {
"Visits": 500
},
"SubRows": [
{
"facebook.com": {
"attributes": {},
"measures": {
"Visits": 100
},
"SubRows": null
},
"google.co.uk": {
"attributes": {},
"measures": {
"Visits": 100
},
"SubRows": null
},
"newsnow.co.uk": {
"attributes": {},
"measures": {
"Visits": 100
},
"SubRows": null
},
"No Referrer": {
"attributes": {},
"measures": {
"Visits": 100
},
"SubRows": null
},
"t.co": {
"attributes": {},
"measures": {
"Visits": 100
},
"SubRows": null
}
}
]
}
]
What I need to access is the names i.e facebook.com etc... and visit numbers for each of the SubRows.
I'm able to get the visit numbers, but I can't work out how to get the names. Please note the names will change constantly as different sites will send different amounts of traffic each day.
Section of my code at the moment where I get the visit numbers:
for(i in dObj){
var data = dObj[i].SubRows;
var sd = dObj[i].start_date;
var ed = dObj[i].end_date;
if(sd == ed){
var timep = ""+ sd;
}
else{
var timep = ""+ sd + "-" + ed;
}
var subRows = data[0];
Logger.log(subRows);
for(i in subRows){
var row = subRows[i];
var rmeasures = row.measures;
var rvis = rmeasures.Visits;
values = [timep,"",rvis]; //Blank string for where the name of the site would go
}
}
I've tried the following links, but none of them seem to have the answer:
Getting JavaScript object key list
How to access object using dynamic key?
How to access key itself using javascript
How do I access properties of a javascript object if I don't know the names?
I'm just using vanilla google apps script as I don't have any experience with Jquery etc...
Any help would be much appreciated!
I usually use a little helper function that looks like this:
var keyVal = function(o) {
var key = Object.keys(o)[0];
return {"key": key, "val":o[key]};
} ;
This will map an object with a variable key to a key/value object {key:...., val:{}}, which is usually convenient enough to work with.
describe.only ("stack overflow answer", function(){
it ("is should create a key/value pair" , function(){
var res = keyVal( {
"facebook.com": {
"attributes": {},
"measures": {
"Visits": 100
},
"SubRows": null
}});
res.key.should.equal('facebook.com');
res.val.attributes.should.deep.equal({});
});
Within the loop, the variable i contains the current key. Replacing the empty string with i should give you what you need.
You might also want to look at some of the more functional tools built into Javascript. Some more concise code might also be more explicit:
data.map(function(datum) {
var timep = datum.start_date == datum.end_date ? datum.end_date :
(data.start_date + "-" + datum.end_date);
return datum.SubRows.map(function(subRow) {
return Object.keys(subRow).map(function(key) {
return [timep, key, subRow[key].measures.Visits];
});
});
});
would return an object something like this:
[
[
[
["2013-12", "facebook.com", 100],
["2013-12", "google.co.uk", 100],
["2013-12", "newsnow.co.uk", 100],
["2013-12", "No Referrer", 100],
["2013-12", "t.co", 100 ]
]
]
]
This just uses map and Object.keys to simplify some of what you're doing with explicit loops.

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