This question already has answers here:
How to get all properties values of a JavaScript Object (without knowing the keys)?
(25 answers)
Closed 1 year ago.
{
pet: {
"0.628": 92694.5,
"8739.836": 96391.94
},
try: {
//same
}
}
When I specify the key, I get the values but i am trying to read all the values without knowing the keys. I have even tried regex, but nothing seems to be working. As you can see i am fairly new. So sorry if this was a stupid question.
console.log(data.pet) // Gives [Object Object]
console.log(data.pet["0.628"])//Gives the value
console.log(data.pet[0])//Gives undefined
I don't see in what context you'd want to access a json object without knowing the keys.
but what you can do is to parse the json file into a javascript object, and call Object.keys() to get the keys of that object
Related
This question already has answers here:
How can I check if an object is an array? [duplicate]
(51 answers)
Closed 1 year ago.
I wrote a utility function for my nextjs project. In there, I got something that I unexpected. I initialised an empty array which be filled with the data later. When I type check that empty array, it shows an object. I don't want an object. I want an array. Why? Could someone told me why does it happen.
strong text
Yes typeof array is an object in javascript
if you want to check one variable is an object or array then you can use
Array.isArray()
console.log(Array.isArray(arr)) // true
console.log(Array.isArray(obj)) // false
This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 3 years ago.
I am having a hard time trying to accessing any elements in my object.
Find below my code that accesses the object from the localStorage and prints it out on the browser console:
var test = localStorage.getItem('transactionData');
console.log(test);
The above code yields:
[{Amount":"15,000","payersNumber":"070505788","waitersName":"Agnes"}]
When I try to access the element waitersName as seen in the code below:
console.log(">> " +test.waitersName);
It yields:
>> undefined
How do I access the various elements in my object?
test is an array with an object in it, you'll need to access the array item first with test[0] and that will return the object, which will then allow you to access its properties.
The data you retrieve from localstorage is a stringified version of the Javascript array. You first have to parse it using
var array = JSON.parse(test);
Then get your elements from the parsed array.
This question already has answers here:
Variable as the property name in a JavaScript object literal? [duplicate]
(3 answers)
Closed 5 years ago.
I am getting several arrays returned from a GET reponse, which I need to access. Since their names can change based on the request, I have a variable specifing which array to use.
However I always get undefined. See this:
console.log(current); // trips_out_201702
console.log(theResponse.current); // undefined
console.log(theResponse.trips_out_201702); // this works
How can I make theResponse.current work such that it returns what current actually stands for? Why do I get undefined there?
When the property key in an object is a variable you can use the square bracket notation to access that property.
console.log(theResponse[current]);
when acessing with dynamic attribute You should do as
theResponse[current] not theResponse.current
You are trying to get array value using object's way.
You should try this one instant variable['keyName']
Good Luck!
This question already has answers here:
Why are two identical objects not equal to each other?
(9 answers)
Closed 6 years ago.
I was going through Map Documentation on MDN. In Examples, under Using Map Object, Object Literal - {} is used as key to store value. But, the value in Map can't be retrieved using Object Literal.
I verified this in Browser Console and found that Object Literal is not equal to itself. Also, the Function Expression - function() {} is not equal to itself.
I couldn't find the reason behind this. If required, I can ask a different question for Function Expression.
Each time you do {}, it creates a new empty object, so when you do {} == {}, you're comparing two different objects. This comparison is done by reference, so it returns false.
This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
JavaScript property access: dot notation vs. brackets?
(17 answers)
Closed 8 years ago.
I need to know why this isn't working. My Javascript code accesses a variable in an object. But it appears not to be working, partly because I can't figure out the syntax.
var obj = {
size:"small",
big:false,
thing:true
}
alert(obj[size]);
I'm just not sure if I got the syntax right…
This will work here.
obj.size //returns small
OR
obj["size"] //returns small
OR
var my_var = "size"
obj[my_var] //returns small
You can reference object values either by:
obj["size"]
or
obj.size
However, there is an exception. For instance, if you have following object with a number key: (Note: key is still a string even if it's defined this way):
var obj = {
1: true
};
You can retrieve it's value only by using: obj["1"]
Hence, using obj.1 will cause a syntax error.
Therefore, your code works if you change it to e.g.: alert(obj["size"]); but I prefer to use console.log(obj["size"]); for debugging. At least, if you are playing with node.js as your tags indicates.
Cheers.