How to update, push object to object? - javascript

This question might already been asked but I'm having some trouble understanding it, I'd like to update my javascript object with new objects.
Object 1 :
var cjson = {};
var t = {
"infos": "apple",
"fields": {
"color":"red",
}
}
cjson['g320fld1'] = t;
Object 2 :
var data {
"fruits": {},
"vegetables": {}
}
Output : I want to push object 1 to object 2 under fruits key. so the ouput look :
{
"fruits": {
"g320fld1": {
"infos": "apple",
"fields": {
"color":"red",
}
},
"vegetables": {}
}
What I tried :
push()
data['fruits'].push(cjson);
Error : ...push() is not a function. (I know push() works on array only so it won't work here.)
update()
data['fruits'].update(cjson);
Error : ...update() is not a function. (this one gives the same error but since it's another dictionary shouldn't it work as expected ?)
How can I solve this problem ?
UPDATE :
Sorry I didn't precise, I don't want to erase older data in fruits.

You can just assign t with the key directly to the data object. As long as your keys(g320fld1 for example) are distinct nothing will be overwritten. I think this makes more sense for what you are trying to do.
var t = {
"infos": "apple",
"fields": {
"color":"red",
}
}
var data = {
"fruits": {},
"vegetables": {}
}
data.fruits['g320fld1'] = t;
console.log(data);

EDIT
You can use Object.assign(srcObject,newProperties) to append new properties,values to an existing object.
var cjson = {};
var t = {
"infos": "apple",
"fields": {
"color":"red"
}
}
cjson['g320fld1'] = t;
var data ={
"fruits": {
otherProperty:"bar"
},
"vegetables": {}
}
Object.assign(data.fruits,cjson);
console.log(data)

Related

How create an object with dynamic key and dynamic array value with javascript

I have an json data and I wanna create a new object of it according a specific property of the json data; The value of this dynamic key should be an array and I need to update this array if a similar key founded in json data; But I got this error and I don't know what is my bug index.js:46 Uncaught TypeError: object[fullDate] is not iterable
function createGridObject(data) {
let object = {};
for (const item of data) {
const date = new Date(item.orderInfo.demandTime);
const fullDate = `${date.getFullYear()}-${date.getMonth()}-${date.getDay()}`;
console.log({fullDate});
object = {
...object,
[fullDate]: [...object[fullDate], ...item],
};
}
console.log({object});
}
[
{
"id": "2c68be90-6186-44ef-a963-4b5f36d9afe4",
"orderInfo": {
"partNumber": "YDN2ZEP279P1",
"type": "FULL",
"origin": "SU-H40V1",
"destination": "41A01L-T1",
"demandTime": "2021-04-13T21:07:01.587440Z",
"externalOrderId": "181788528",
"containerType": "VW0001",
"received": "2021-04-13T21:02:02.567298Z",
"trailerPosition": null
},
},
{
"id": "1460b736-d6f5-4187-8acc-74f748c8197a",
"orderInfo": {
"partNumber": "",
"type": "EMPTY",
"origin": "SU-H40V1",
"destination": "42A05L-T1",
"demandTime": "2021-04-13T22:27:21.099507Z",
"externalOrderId": "891755586",
"containerType": "VW0001",
"received": "2021-04-13T22:22:24.268943Z",
"trailerPosition": null
}
},
]
If object[fullDate] doesn't exist, [...object[fullDate], ___] is trying to use iterable spread on undefined. You can't do that. (People sometimes get confused, because you can use object property spread on undefined. But not iterable spread.)
Instead:
object = {
...object,
[fullDate]: [...object[fullDate] ?? [], ...item],
// −−−−−−−−−−−−−−−−−−−−−−−−−−−−−^^^^^^
};
That way, if it's undefined, you'll spread [] instead.
Or use a conditional:
object = {
...object,
[fullDate]: object[fullDate] ? [...object[fullDate], ...item] : [...item],
};

Javascript using variable as key to get nested object value

Assume I have the following object:
var jsonObj = {
"response":{
"result":{
"status":{
"name": "Eric"
}
}
}
}
And now i'd like to dynamically access a nested property:
jsonKey = "response.result.status.name";
console.log("the status is: " + jsonObj.jsonKey); //I cannot call jsonObj.jsonKey here
Is there any way to achieve this?
You cannot access a deeply nested property as simple as you expect. Instead you need to use the obj[propertyNameAsString] syntax to dive deeper into the response one by one.
This would be one way of getting there:
let response = {
"response": {
"method": "GetStatus",
"module": "Module",
"data": null,
"result": {
"status": {
"name": "Eric"
},
"id": 1
},
"result_code": {
"error_code": 0
}
}
}
let keyString = "response.result.status.name"
let keyArray = keyString.split('.'); // [ "response", "result", "status", "name" ]
var result = response;
for (key of keyArray) {
result = result[key]
}
console.log(result)
Please be aware that this is not failsafe against cases where one of those strings in keyArray does not exist as a property on the preceding object.
You can do like this something['bar']
Where bar is your variable that has been converted to string, in our case:
jsonObj[`${jsonKey}`]

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.

Add data to end of ko.observablearray

I'm trying to add data to the end of an observable array but it's just not working as expected. I bet it is something minor but I just can't get my head around it.
What I am doing:
self.businesses = ko.observableArray();
function Business(business) {
var self = this;
self.BusinessID = ko.observable(business.BusinessID );
self.Type = ko.observable(business.Type);
self.Location = ko.observable(business.Location);
}
/*ajax get array of businesses as follows:
[
{
"$id": "1",
"BusinessID ": 62,
"Type": "Data",
"Location": "Data"
},
{
"$id": "2",
"BusinessID ": 63,
"Type": "Data",
"Location": "Data"
},
{
"$id": "3",
"BusinessID ": 64,
"Type": "Data",
"Location": "Data",
} ]
*/
var mappedBusinesses = $.map(data, function (business) { return new Business(business) });
self.businesses(mappedBusinesses);
This all works as expected and the obersablearray is populated.
However if I go to add another business, it wont work. For example, if I call the ajax that returns this (as newBusiness):
{
"$id": "1",
"BusinessID ": 68,
"Type": "Data",
"Location": "Data"
}
and I do:
self.businesses().push(newBusiness);
It adds to the array as an "Object" not a Business. So I thought I would do:
var bus = $.map(newBusiness, function (business) { return new Business(business) });
self.businesses().push(bus);
But I get the error in the JS console "Uncaught TypeError: Cannot read property 'BusinessID' of null
So I made a new var and added the brackets: [] in and it adds to the observable array but not as a "Business" object but rather as an "Array[1]" object at the end and this doesn't function as per the others. Code as follows:
var newBus = {
BusinessID: newBusiness.BusinessID,
Type: newBusiness.Type,
Location: newBusiness.Location
}
var bus = $.map(newBus, function (business) { return new Business(business) });
self.businesses().push(bus);
As mentioned this adds to the observable array but doesn't actually add as a "business" object but rather as an "array[1]" object.
I bet it's something so basic but just can't get it working!
Argh I knew it would be simple!
It was posting the whole array to the ObservableArray...not just the object.
The fix:
self.businesses.push(newBusiness[0])
Had to add the [0] in to get it to push the actual data into the array, not the object!
Thanks for the answers!
You're evaluating the array with your push:
self.businesses().push(newBusiness);
Observable Arrays have their own array functions, you should just do this (no parens):
self.businesses.push(newBusiness);
See this page: http://knockoutjs.com/documentation/observableArrays.html

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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