object.assign is only perform the direct merge but its not working for nested json.
If anyone worked on this, could you please share the steps.
For example,I want to update the phone number and city of the user. City is under the location property. How should i update the value of city?
Example:
const user = {
name: "Liya",
phone: 12345,
location: {
city: "Camden",
country: "UK"
}
};
const updates = {
name: "David",
phone: 12345678,
location: {
city: "Smithfield"
}
};
Output should be like this:
console.log(Object.assign({}, user, updates));
{
name: 'Liya',
phone: 12345678,
location: {
country: 'UK',
city: 'Smithfield'
}
}
I'm assuming the name should be David since that's the name in the updates.
Based on #Han Moe Htet's comment, I used code from Vincent on that response. I used his because it does not require any external libraries, which Snowflake currently does not allow for Javascript UDFs.
There's an important consideration with this code. It uses recursion, and Snowflake UDFs have rather limited stack depth. If you have a highly nested object, it could run out of stack depth.
set USR = $${
name: "Liya",
phone: 12345,
location: {
city: "Camden",
country: "UK"
}
}$$;
set UPDATES = $${
name: "David",
phone: 12345678,
location: {
city: "Smithfield"
}
}$$;
create or replace function MERGE_OBJECTS("obj1" object, "obj2" object)
returns object
language javascript
strict immutable
as
$$
return merge(obj1, obj2);
function merge(current, updates) {
for (key of Object.keys(updates)) {
if (!current.hasOwnProperty(key) || typeof updates[key] !== 'object') current[key] = updates[key];
else merge(current[key], updates[key]);
}
return current;
}
$$;
with x as
(
select parse_json($USR) as USR, parse_json($UPDATES) as UPDATES
)
select merge_objects(USR, UPDATES) from X;
Related
I am trying to turn an array of JavaScript objects into a URL string with params, as seen below:
const objects = [{
firstName: "John",
lastName: "Doe",
age: 46
},
{
country: "France",
lastName: "Paris"
}
]
let entry_arr = [];
objects.forEach(obj => {
Object.entries(obj).forEach(entry => {
entry_arr.push(entry.join('='));
});
});
let entry_str = entry_arr.join('&');
console.log(entry_str);
By all appearances, the above code works. There is a problem though.
The problem
As you can see, I have 2 nested forEach loops. For better performance, I wish I knew how to avoid this nesting and instead use only one forEach loop.
How can I achieve the same result with inly one loop?
Merging each object inside the array in a main one would be the only solution I can think of. ( I assumed lastName: paris was a typo)
const objects = [{
firstName: "John",
lastName: "Doe",
age: 46
},
{
country: "France",
city: "Paris"
}
]
const obj = objects.reduce((acc, obj) => Object.assign(acc, obj), {});
const entry_str = Object.entries(obj).map(entry =>
entry.join('=')
).join('&');
console.log(entry_str);
The answer provided by Nina stil uses a nested loop, instead of using forEach, map is used.
For special character handling i strongly recommend to use the URLSearchParams class.
I would advise to join the array of objects in one single objects with reduce and import the entries in a URLSearchParams
const objects = [
{ firstName: "John", lastName: "Doe", age: 46 }, { country: "France", lastName: "Paris" }];
let reduced = objects.reduce((acc, object) => Object.assign(acc, object))
let params = new URLSearchParams(reduced);
console.log(reduced);
console.log(params.toString());
At least, you need to map the entries with joining key and value and join the nested entries and outer array.
const
objects = [{ firstName: "John", lastName: "Doe", age: 46 }, { country: "France", lastName: "Paris" }],
result = objects
.map(object => Object
.entries(object)
.map(entry => entry.join('='))
.join('&')
)
.join('&');
console.log(result);
I have a JavaScript object like below
const obj = {
name: 'Jone',
location: {
presentAddress: {
livingAddress: {
City: {name: 'New York'},
Country: {name: 'USA'},
}
}
}
}
I'm trying to change city name New York to London
So, I have tried below code
console.log({
...obj,
location:{
...obj.location,
presentAddress:{
...obj.location.presentAddress,
livingAddress: {
...obj.location.presentAddress.livingAddress,
City:{
...obj.location.presentAddress.livingAddress.City,
name: "London"
}
}
}
}
})
It's working fine, My question is has there any shorter way to do this change?
Try setting the nested property directly.
obj.location.presentAddress.livingAddress.City.name = "London"
Given an array such as:
people = [
{
name: 'Bob',
sex: 'male',
address:{
street: 'Elm Street',
zip: '12893'
}
},
{
name: 'Susan',
sex: 'female',
address:{
street: 'Hickory Street',
zip: '00000'
}
}
]
I am trying to write a function which will alter specific instances of '00000' in the nested field 'zip' to the string '12893' and return a new array identical to the initial array except with the corrected values. My attempt at a function so far is:
function zipFix (initialArray) {
return initialArray.map(function(person) {
if(person.address.zip === '00000')
person.address.zip = "12893"
return person
});
}
I know this function is altering the values in 'initialArray', which isn't supposed to happen. How can I go about writing my function so that I can effectively use the map function to create a new, corrected array? Thanks.
While map-ing over the values, you will need to create a copy of each object. The easiest way to do so is with the object spread syntax ({...obj}).
This will "spread" all the values (name, adress, etc) into a new object. So any changes won't mutate it. However, it's "shallow" meaning it will be a new object but its values are the same. So since address is also an object we need to copy that as well, hence the reason for the nested spread of the address value as well.
people = [{
name: 'Bob',
sex: 'male',
address: {
street: 'Elm Street',
zip: '12893'
}
},
{
name: 'Susan',
sex: 'female',
address: {
street: 'Hickory Street',
zip: '00000'
}
}
]
function zipFix(initialArray) {
return initialArray.map(function(person) {
// Create a new "copy" of the person. Using object spread
// will create a "shallow" copy, so since address is also an
// object it will have to be spread (same for other objects that might
// be mutated).
const newValue = { ...person, address: { ...person.address }}
if (newValue.address.zip === '00000') {
newValue.address.zip = "12893";
}
return newValue
});
}
console.log(zipFix(people))
console.log(people) // unchanged
You need to return values from callback function too, also make a copy of element before assigning to avoid mutability
const people = [{name: 'Bob',sex: 'male',address:{street: 'Elm Street',zip: '12893'}},{name: 'Susan',sex: 'female',address:{street: 'Hickory Street',zip: '00000'}}]
function zipFix (initialArray) {
return initialArray.map(function(person) {
let newObj = JSON.parse(JSON.stringify(person))
if(newObj.address.zip === '00000')
newObj.address.zip ="12893"
return newObj
});
}
console.log(zipFix(people))
people = [{
name: 'Bob',
sex: 'male',
address: {
street: 'Elm Street',
zip: '12893'
}
},
{
name: 'Susan',
sex: 'female',
address: {
street: 'Hickory Street',
zip: '00000'
}
}
]
function zipFix (initialArray) {
return (initialArray.map(({address, ...p}) => (
address.zip !== '00000' ? { ...p, address } : {
...p,
address: {
...address,
zip: '12893'
}
}
)));
}
console.log(zipFix(people));
You can do:
const people = [{name: 'Bob',sex: 'male',address: {street: 'Elm Street',zip: '12893'}},{name: 'Susan',sex: 'female',address: {street: 'Hickory Street',zip: '00000'}}]
const zipFix = people.map(({address, ...p}) => ({
...p,
address: {
...address,
zip: address.zip === '00000' ? '12893' : address.zip
}
}))
console.log(zipFix)
I am trying to add multiple objects- Company Names into listBox Companies. I used $scope.companies.push(newCompany[0].name); to add the company into the list. But only the first object's company gets added because I used newCompany[0].name.
Now, how do I add the second company name into the list without entering newCpmpany[1].name ? Say there are 50 companies, I cannot add all 50 by doing this. Is there a better way to add all the names in one go? like a loop or incrementing the element or something? Looking for some help. Thanks in advance.
var newCompany = [{
name: "Huawei", // -->COMPANY NAME
email: "Drath#yahoo.com",
phone: "123-123-1234",
owner: "Drath",
street: "Gin Blvd",
city: "Austin",
country: "USA",
duns:"123112321",
type: "buyer"
},
{
name: "Asus", // -->COMPANY NAME
email: "Vadar#yahoo.com",
phone: "999-123-8888",
owner: "Vadar",
street: "Vince Blvd",
city: "Dallas",
country: "USA",
duns: "123100000",
type: "supplier"
}];
window.localStorage.setItem("newCompany", JSON.stringify(newCompany));
$scope.companies = [];
var newCompany = JSON.parse(localStorage.getItem("newCompany"));
$scope.companies.push(newCompany[0].name);
You can try with spread
$scope.companies.push(...newCompany.map(item => item.name));
or why do you need exactly push? why don't you just init $scope.companies with exact values
var newCompany = JSON.parse(localStorage.getItem("newCompany"));
$scope.companies = newCompany.map(item => item.name)
If spread is not supported just a regular splice of array can be used
var names = newCompany.map(function(company){return company.name});
$scope.companies.splice(-1, 0, names);
I have an array of javascript objects that represent users, like so:
[
{ userName: "Michael",
city: "Boston"
},
{ userName: "Thomas",
state: "California",
phone: "555-5555"
},
{ userName: "Kathrine",
phone: "444-4444"
}
]
Some of the objects contain some properties but not others. What I need is a clean way to ensure ALL objects get the same properties. If they don't exist, I want them to have an empty string value, like so:
[
{ userName: "Michael",
city: "Boston",
state: "",
phone: ""
},
{ userName: "Thomas",
city: "",
state: "California",
phone: "555-5555"
},
{ userName: "Kathrine",
city: "",
state: "",
phone: "444-4444"
}
]
Update
I should have been a little more specific. I was looking for an option that would handle this situation dynamically, so I don't have to know the properties ahead of time.
For jQuery specific, the $.extend() option is a good one, but will only work if you know ALL the properties ahead of time.
A few have mentioned that this should probably be a server-side task, and while I normally agree with that, there are two reasons I'm not handling this at the server-side:
1) it will be a smaller JSON object if say 900 of 1000 objects only contain 1 of a possible 9 properties.
2) the "empty" properties need to be added to satisfy a JS utility that could be replaced in the future with something that doesn't care if some properties are missing.
Since you are using jQuery you can abuse $.extend
function Person(options){
return $.extend({
userName:"",
city: "",
state:"",
phone: ""
},options);
}
$.map([{}],Person)
update
Heres a way to have dynamic default properties
function mapDefaults(arr){
var defaultProperties = {}
for(var i =0; i < arr.length; i++){
$.each(arr[i],function(key){
defaultProperties[key] = "";
});
}
function Defaulter(obj){
return $.extend({},defaultProperties,obj);
}
return $.map(arr, Defaulter);
}
mapDefaults([{a:"valA"},{b:"valB"}]);
/* produces:
[{a:"valA",b:""},{a:"",b:"valB"}]
*/
Something you might try is creating a coalescing function:
function coalesceValues(val){
switch(val)
case undefined:
case null:
return '';
break;
default:
return val;
break;
}
}
Or if you wanted to forego customization for simplicity:
function coalesceValues(val){
return val || '';
}
And then apply it when assigning variables:
var city = coalesceValues(obj.city);
This way you don't need to do any crazy breakdown to array and loop or anything, you can apply it to whatever you want, and you can also customize the values you want to coalesce.
Just offering an alternative idea.
The way that is easiest to understand is probably to make a function that accepts an object and uses if statements as existence checks, assigning a default value if it doesn't find it.
function normalize(object) {
if(typeof object.userName === 'undefined') {
object.userName = 'Default Value';
}
if(typeof object.city === 'undefined') {
object.city = 'Default Value';
}
if(typeof object.state === 'undefined') {
object.state = 'Default Value';
}
if(typeof object.phone === 'undefined') {
object.phone = 'Default Value';
}
return object;
}
var userArray = [{},{},{}].map(normalize);
We can also go the constructor route and provide default values on object creation.
function User (data) {
this.userName = data.userName || 'Default Value';
this.city = data.city || 'Default Value';
this.state = data.state || 'Default Value';
this.phone = data.phone || 'Default Value';
return this;
}
var userArray = [{},{},{}].map(function(o){
return new User(o);
});
Of course this depends on one specific type of data and won't extend to other properties and isn't very DRY, but as I said, this is probably the easiest to understand from a beginner's standpoint.
var list = [
{ userName: "Michael",
city: "Boston"
},
{ userName: "Thomas",
state: "California",
phone: "555-5555"
},
{ userName: "Kathrine",
phone: "444-4444"
}
];
for(var i = 0; i < list.length; i++){
if(list[i].state === undefined)
list[i].state = "";
if(list[i].phone === undefined)
list[i].phone = "";
};
console.log(list);
http://jsfiddle.net/g5XPk/1/
This should probably be a server-side task, but..
If you know all the possible properties ahead of time, you could do this:
http://jsfiddle.net/BMau9/
var properties = ['userName', 'city', 'state', 'phone'];
var data = [{
userName: "Michael",
city: "Boston"
}, {
userName: "Thomas",
state: "California",
phone: "555-5555"
}, {
userName: "Kathrine",
phone: "444-4444"
}];
for (var i in data) {
for (var j in properties) {
data[i][properties[j]] = data[i][properties[j]] || '';
}
}
Fiddle
This function stores unique object keys in an array and so you can run your array of objects through it and then use one of the other supplied answers to add the keys to the objects if they do not exist:
function uniqueKeys(){
var keys=[];
function getUniqueKeys(){
return keys
}
function addObject(obj){
for (var k in obj){
keys = _.union(keys,[k]);
}
}
return {
addObj: addObject,
getKeys: getUniqueKeys
}
}
Usage:
var objArr = [{ userName: "Michael", city: "Boston" },
{ userName: "Thomas", state: "California", phone: "555-5555"},
{ userName: "Kathrine",phone: "444-4444" }];
var uniq = new uniqueKeys();
_.each(objArr, function(v){
uniq.addObj(v)
});
var keys = uniq.getKeys();
alert(keys);
vanilla js
let A = [
{
userName: "Michael",
city: "Boston",
},
{
userName: "Thomas",
state: "California",
phone: "555-5555",
},
{
userName: "Kathrine",
phone: "444-4444",
},
];
// set-difference
const diff = (a,b) => new Set([...a].filter((x) => !b.has(x)));
// all keys
const K = new Set(arr.map(o => Object.keys(o)).flat());
// add missing keys and default vals
A.forEach((e,i) => diff(K, new Set(Object.keys(e))).forEach(k => A[i][k] = ""));