I have a function that takes in an Array, iterates over it finding all Objects and displays them to the UI.
In rare cases, I have to supply an Object (result from a WS as application/JSON) which is not an Array by default and hence my function fails to iterate over it and display on the UI.
In normal cases my Array looks like this:
[
{ "name" : "foo"},
{ "name" : "bar"},
{ "name" : "baz"}
]
and this works like it is supposed to. However, sometimes the data I get could be this:
{ "name" : "I am not in a List"}
and my function that takes in an array looks like this:
function loadJSONIntoUI(data) {
for (var aMsg = 0; aMsg < data.length(); aMsg++) {
// Do something with each `index` in the List
}
}
Is there a way I can detect that the single object which is not an array is an odd one and probably put it into a List on the fly and pass it to a function?
So far I have tried to use typeof and also tried to create a new Array on the fly and push my object into it but it prints out a 1 when I do that.
A one liner using Array.prototype.flat:
[couldBeArray].flat()
Examples:
const anObj = {name: "Hi"};
const anArr = [{name: "Hi"}];
const wrapped1 = [anObj].flat()
const wrapped2 = [anArr].flat()
console.log(wrapped1); // wrapped1 is [{name: "Hi"}]
console.log(wrapped2); // wrapped2 is [{name: "Hi"}]
You can simply use Array.concat() to auto-wrap an object into an array:
const obj = {name: "foo"};
const arr = [{name: "bar"}];
const result1 = [].concat(obj); // result1 is [{name: "foo"}]
const result2 = [].concat(arr); // result2 is [{name: "bar"}]
console.log(result1)
console.log(result2)
you can transform it in an array if is not and let iterate one time:
function loadJSONIntoUI(data) {
if(!(data instanceof Array)){
data = [data];
}
for (var aMsg = 0; aMsg < data.length; aMsg++) {
// Do something with each `index` in the List
}
}
Also, length doesn't need to be called like a method.
Let me know if it works
Cheers
Array.isArray can be used to achieve what you need:
function loadJSONIntoUI(data) {
if(!Array.isArray(data)) {
data = [data];
}
for (var aMsg = 0; aMsg < data.length(); aMsg++) {
// Do something with each `index` in the List
}
}
You need to check for an array and fix an error - should be just data.length, no brackets. See code below, check demo - https://fiddle.jshell.net/ermakovnikolay/fgedaubm/
function loadJSONIntoUI(data) {
var data = Array.isArray(data) ? data : [ data ];
for (var aMsg = 0; aMsg < data.length; aMsg++) {
// Do something with each `index` in the List
console.log(data[aMsg]);
}
}
You can use Array.of(). So in your case Array.of(data) returns [{ "name" : "I am not in a List"}]
Related
What is Wrong in below code? getting last index value.in all JSON Object
let arr = ['apple','banana','cherry'];
let dataJson=[];
let json={}
console.log('lent',arr.length);
for(var i = 0; i<arr.length;i++) {
json.name=arr[i];
json.type="fruit";
dataJson.push(json);
}
You are passing the object reference within the array. In the last iteration the object will have cherry which is reflected in all objects passed within the array. Instead, use Object.assign to create new object.
let arr = ['apple','banana','cherry'];
let dataJson=[];
let json={}
for(var i = 0; i<arr.length;i++) {
json.name=arr[i];
json.type="fruit";
dataJson.push(Object.assign({}, json));
}
console.log(dataJson);
You can achieve the same functionality using reduce.
let fruits = ['apple','banana','cherry'];
const output = fruits.reduce((a, fruit) => {
a.push({"name": fruit, type: "fruit"});
return a;
}, []);
console.log(output);
I would use map to do it
const arr = ['apple','banana','cherry']
const dataJson = arr.map(fruitName => ({name: fruitName, type: 'fruit'}))
console.log(dataJson)
It looks like you're trying to convert your array of string fruit names in to a JavaScript Object. Currently, your code is always overwritting the name property with every iteration. I would suggest pushing an object in every iteration instead.
let arr = ['apple','banana','cherry'];
let dataJson = [];
console.log('lent',arr.length);
for(var i = 0; i <arr.length; i++) {
dataJson.push({name: arr[i], type: 'fruit'} )
}
console.log(dataJson);
// Modern way of doing it with Array.map
const data = ['apple','banana','cherry'].map( d => ( { name: d, type: 'fruit' } ) );
console.log(data);
In other news, JSON is a string. You're working with a JavaScript Object.
I have 2 arrays namely,
configdata = ["assignee", "shortDesc"];
ticketarray = ["Tom","testDesc"];
I want to store the values as a key value pair in another array, something like this:
ticketData = ["assignee":"Tom","shortDesc":"testDesc"];
Kindly note that the array values are dynamic, so I cannot hardcode them.
Is there a way to do so? I am able to achieve the above said requirement but the length always shows 0. This is the code that I am using:
configdata.Incident_Field.forEach(function (k, i) {
this[k] = ticketarray[i];
}, ticketData);
Other people have explained why your code did not work. I am providing another solution using reduce.
const configdata = ["assignee", "shortDesc"];
const ticketarray = ["Tom", "testDesc"];
let ticketData = configdata.reduce((result, value, index) => {
result[value] = ticketarray[index];
return result;
}, {});
console.log(ticketData);
Output:
{
assignee: "Tom",
shortDesc: "testDesc"
}
The below is not a valid structure in JavaScript:
ticketData = ["assignee":"Tom","shortDesc":"testDesc"];
What you need is a JavaScript object. The best you can do is:
Make sure both the array lengths are same.
Associate the key and value by creating a new object.
Use Object.keys(obj).length to determine the length.
Start with the following code:
configdata = ["assignee", "shortDesc"];
ticketarray = ["Tom", "testDesc"];
if (configdata.length == ticketarray.length) {
var obj = {};
for (var i = 0; i < configdata.length; i++)
obj[configdata[i]] = ticketarray[i];
}
console.log("Final Object");
console.log(obj);
console.log("Object's Length: " + Object.keys(obj).length);
The above will give you an object of what you liked, a single variable with all the values:
{
"assignee": "Tom",
"shortDesc": "testDesc"
}
I know it's simple, but I don't get it.
I have this code:
// My object
const nieto = {
label: "Title",
value: "Ramones"
}
let nietos = [];
nietos.push(nieto.label);
nietos.push(nieto.value);
If I do this I'll get a simple array:
["Title", "Ramones"]
I need to create the following:
[{"01":"Title", "02": "Ramones"}]
How can I use push() to add the object into the nietos array?
You have to create an object. Assign the values to the object. Then push it into the array:
var nietos = [];
var obj = {};
obj["01"] = nieto.label;
obj["02"] = nieto.value;
nietos.push(obj);
Create an array of object like this:
var nietos = [];
nietos.push({"01": nieto.label, "02": nieto.value});
return nietos;
First you create the object inside of the push method and then return the newly created array.
can be done like this too.
// our object array
let data_array = [];
// our object
let my_object = {};
// load data into object
my_object.name = "stack";
my_object.age = 20;
my_object.hair_color = "red";
my_object.eye_color = "green";
// push the object to Array
data_array.push(my_object);
Using destructuring assignment (ES6)
const nieto = {label: 'title', value: 'ramones' }
const modifiedObj = {01: nieto.label, 02: nieto.value}
let array = [
{03: 'asd', 04: 'asd'},
{05: 'asd', 06: 'asd'}
]
// push the modified object to the first index of the array
array = [modifiedObj, ...array]
console.log(array)
If you'd like to push the modified object to the last index of the array just change the destructured array ...array to the front.
array = [...array, modifiedObj]
Well, ["Title", "Ramones"] is an array of strings. But [{"01":"Title", "02", "Ramones"}] is an array of object.
If you are willing to push properties or value into one object, you need to access that object and then push data into that.
Example:
nietos[indexNumber].yourProperty=yourValue; in real application:
nietos[0].02 = "Ramones";
If your array of object is already empty, make sure it has at least one object, or that object in which you are going to push data to.
Let's say, our array is myArray[], so this is now empty array, the JS engine does not know what type of data does it have, not string, not object, not number nothing. So, we are going to push an object (maybe empty object) into that array. myArray.push({}), or myArray.push({""}).
This will push an empty object into myArray which will have an index number 0, so your exact object is now myArray[0]
Then push property and value into that like this:
myArray[0].property = value;
//in your case:
myArray[0]["01"] = "value";
I'm not really sure, but you can try some like this:
var pack = function( arr ) {
var length = arr.length,
result = {},
i;
for ( i = 0; i < length; i++ ) {
result[ ( i < 10 ? '0' : '' ) + ( i + 1 ) ] = arr[ i ];
}
return result;
};
pack( [ 'one', 'two', 'three' ] ); //{01: "one", 02: "two", 03: "three"}
The below solution is more straight-forward. All you have to do is define one simple function that can "CREATE" the object from the two given items. Then simply apply this function to TWO arrays having elements for which you want to create object and save in resultArray.
var arr1 = ['01','02','03'];
var arr2 = ['item-1','item-2','item-3'];
resultArray = [];
for (var j=0; j<arr1.length; j++) {
resultArray[j] = new makeArray(arr1[j], arr2[j]);
}
function makeArray(first,second) {
this.first = first;
this.second = second;
}
This solution can be used when you have more than 2 properties in any object.
const nieto = {
label: "Title",
value: "Ramones"
}
let nietos = [];
let xyz = Object.entries(nieto)
xyz.forEach((i,j)=>{
i[0] = `${(j+1).toLocaleString("en-US", {
minimumIntegerDigits: 2,
useGrouping: false,
})}`
})
nietos.push(Object.fromEntries(xyz))
I have this:
var one = ['12','24','36'];
var two = ['10','20','30'];
If I do:
alert(one) I have: 12,24,36. And it's ok.
I need to have the name of the array from another function, where I call it from a for like this:
var test = [one,two]
for (i = 0; i < test.length; i++) {
alert(test[i]);
}
I have "12,24,36" and then "10,20,30" in the alert, but I need the name of the array, not the content. How to do?
I want two alert with: "one" and "two", the name of Array.
Use an object to hold your arrays:
var obj = {
one: ['12','24','36'],
two: ['10','20','30']
}
for (var p in obj) {
console.log(p); // log the key
}
Alternatively you can use Object.keys(obj) to retrieve an array of the object keys.
And if you need to log the array contents:
for (var p in obj) {
console.log(obj[p]); // log the array contents
}
DEMO
Yes, I agree with elad.chen. You can try something like:
var objects = [
{name:"one",value:['12','24','36']},
{name:"two",value:['12','24','36']}
];
for(var i=0;i<objects.length;i++){
console.log(objects[i].name);
console.log(objects[i].value);
}
You can use an "Object Literal" and use the property name as the name, and the value as the array..
For example:
var arrays = {
"one": [1,2,3],
"two": [1,2,3]
}
for ( var k in arrays ) {
alert('"Array name" = ' + k)
alert('"Array value" = ' + arrays[k].toString() )
}
At some place, the name must be set. While Javascript is can add properties to objects, this can be used for a name property without changing the behaviour of the arrays.
var one = ['12', '24', '36'];
one.name = 'one';
var two = ['10', '20', '30'];
two.name = 'two';
var test = [one, two], i;
for (i in test) {
document.write(test[i].name + '<br>');
}
I have a variable which is an array and I want every element of the array to act as an object by default. To achieve this, I can do something like this in my code.
var sample = new Array();
sample[0] = new Object();
sample[1] = new Object();
This works fine, but I don't want to mention any index number. I want all elements of my array to be an object. How do I declare or initialize it?
var sample = new Array();
sample[] = new Object();
I tried the above code but it doesn't work. How do I initialize an array of objects without using an index number?
Use array.push() to add an item to the end of the array.
var sample = new Array();
sample.push(new Object());
To do this n times use a for loop.
var n = 100;
var sample = new Array();
for (var i = 0; i < n; i++)
sample.push(new Object());
Note that you can also substitute new Array() with [] and new Object() with {} so it becomes:
var n = 100;
var sample = [];
for (var i = 0; i < n; i++)
sample.push({});
Depending on what you mean by declaring, you can try using object literals in an array literal:
var sample = [{}, {}, {} /*, ... */];
EDIT: If your goal is an array whose undefined items are empty object literals by default, you can write a small utility function:
function getDefaultObjectAt(array, index)
{
return array[index] = array[index] || {};
}
Then use it like this:
var sample = [];
var obj = getDefaultObjectAt(sample, 0); // {} returned and stored at index 0.
Or even:
getDefaultObjectAt(sample, 1).prop = "val"; // { prop: "val" } stored at index 1.
Of course, direct assignment to the return value of getDefaultObjectAt() will not work, so you cannot write:
getDefaultObjectAt(sample, 2) = { prop: "val" };
You can use fill().
let arr = new Array(5).fill('lol');
let arr2 = new Array(5).fill({ test: 'a' });
// or if you want different objects
let arr3 = new Array(5).fill().map((_, i) => ({ id: i }));
Will create an array of 5 items. Then you can use forEach for example.
arr.forEach(str => console.log(str));
Note that when doing new Array(5) it's just an object with length 5 and the array is empty. When you use fill() you fill each individual spot with whatever you want.
After seeing how you responded in the comments. It seems like it would be best to use push as others have suggested. This way you don't need to know the indices, but you can still add to the array.
var arr = [];
function funcInJsFile() {
// Do Stuff
var obj = {x: 54, y: 10};
arr.push(obj);
}
In this case, every time you use that function, it will push a new object into the array.
You don't really need to create blank Objects ever. You can't do anything with them. Just add your working objects to the sample as needed. Use push as Daniel Imms suggested, and use literals as Frédéric Hamidi suggested. You seem to want to program Javascript like C.
var samples = []; /* If you have no data to put in yet. */
/* Later, probably in a callback method with computed data */
/* replacing the constants. */
samples.push(new Sample(1, 2, 3)); /* Assuming Sample is an object. */
/* or */
samples.push({id: 23, chemical: "NO2", ppm: 1.4}); /* Object literal. */
I believe using new Array(10) creates an array with 10 undefined elements.
You can instantiate an array of "object type" in one line like this (just replace new Object() with your object):
var elements = 1000;
var MyArray = Array.apply(null, Array(elements)).map(function () { return new Object(); });
Well array.length should do the trick or not? something like, i mean you don't need to know the index range if you just read it..
var arrayContainingObjects = [];
for (var i = 0; i < arrayContainingYourItems.length; i++){
arrayContainingObjects.push {(property: arrayContainingYourItems[i])};
}
Maybe i didn't understand your Question correctly, but you should be able to get the length of your Array this way and transforming them into objects. Daniel kind of gave the same answer to be honest. You could just save your array-length in to his variable and it would be done.
IF and this should not happen in my opinion you can't get your Array-length. As you said w/o getting the index number you could do it like this:
var arrayContainingObjects = [];
for (;;){
try{
arrayContainingObjects.push {(property: arrayContainingYourItems[i])};
}
}
catch(err){
break;
}
It is the not-nice version of the one above but the loop would execute until you "run" out of the index range.
//making array of book object
var books = [];
var new_book = {id: "book1", name: "twilight", category: "Movies", price: 10};
books.push(new_book);
new_book = {id: "book2", name: "The_call", category: "Movies", price: 17};
books.push(new_book);
console.log(books[0].id);
console.log(books[0].name);
console.log(books[0].category);
console.log(books[0].price);
// also we have array of albums
var albums = []
var new_album = {id: "album1", name: "Ahla w Ahla", category: "Music", price: 15};
albums.push(new_album);
new_album = {id: "album2", name: "El-leila", category: "Music", price: 29};
albums.push(new_album);
//Now, content [0] contains all books & content[1] contains all albums
var content = [];
content.push(books);
content.push(albums);
var my_books = content[0];
var my_albums = content[1];
console.log(my_books[0].name);
console.log(my_books[1].name);
console.log(my_albums[0].name);
console.log(my_albums[1].name);
This Example Works with me.
Snapshot for the Output on Browser Console
Try this-
var arr = [];
arr.push({});
const sample = [];
list.forEach(element => {
const item = {} as { name: string, description: string };
item.name= element.name;
item.description= element.description;
sample.push(item);
});
return sample;
Anyone try this.. and suggest something.
Use array.push() to add an item to the end of the array.
var sample = new Array();
sample.push(new Object());
you can use it
var x = 100;
var sample = [];
for(let i=0; i<x ;i++){
sample.push({})
OR
sample.push(new Object())
}
Using forEach we can store data in case we have already data we want to do some business login on data.
var sample = new Array();
var x = 10;
var sample = [1,2,3,4,5,6,7,8,9];
var data = [];
sample.forEach(function(item){
data.push(item);
})
document.write(data);
Example by using simple for loop
var data = [];
for(var i = 0 ; i < 10 ; i++){
data.push(i);
}
document.write(data);
If you want all elements inside an array to be objects, you can use of JavaScript Proxy to apply a validation on objects before you insert them in an array. It's quite simple,
const arr = new Proxy(new Array(), {
set(target, key, value) {
if ((value !== null && typeof value === 'object') || key === 'length') {
return Reflect.set(...arguments);
} else {
throw new Error('Only objects are allowed');
}
}
});
Now if you try to do something like this:
arr[0] = 'Hello World'; // Error
It will throw an error. However if you insert an object, it will be allowed:
arr[0] = {}; // Allowed
For more details on Proxies please refer to this link:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy
If you are looking for a polyfill implementation you can checkout this link:
https://github.com/GoogleChrome/proxy-polyfill
The below code from my project maybe it good for you
reCalculateDetailSummary(updateMode: boolean) {
var summaryList: any = [];
var list: any;
if (updateMode) { list = this.state.pageParams.data.chargeDefinitionList }
else {
list = this.state.chargeDefinitionList;
}
list.forEach((item: any) => {
if (summaryList == null || summaryList.length == 0) {
var obj = {
chargeClassification: item.classfication,
totalChargeAmount: item.chargeAmount
};
summaryList.push(obj);
} else {
if (summaryList.find((x: any) => x.chargeClassification == item.classfication)) {
summaryList.find((x: any) => x.chargeClassification == item.classfication)
.totalChargeAmount += item.chargeAmount;
}
}
});
if (summaryList != null && summaryList.length != 0) {
summaryList.push({
chargeClassification: 'Total',
totalChargeAmount: summaryList.reduce((a: any, b: any) => a + b).totalChargeAmount
})
}
this.setState({ detailSummaryList: summaryList });
}
var ArrayofObjects = [{}]; //An empty array of objects.