for loop gives only last value in javascript

Question

I have created variable outside to get values from inside but I only get last value in both variables.

var categoryProductid;
var PPProducttitle;

for (var key in UpdatedCategory) {

  const actual = UpdatedCategory[key]
  var categoryProductid = actual.id;
  var PPProducttitle = actual.title;

  console.log(PPProducttitle)
  console.log(categoryProductid)
}

console.log(PPProducttitle)
console.log(categoryProductid)

when I do console.logs() from inside and outside of for loop I get two different values.

Any help will be appreciated thank you!!!!!

i don't expect them to give different values, i only want same values. — swapnil agrawal, Jan 18 '22 at 08:05
_"when I do console.logs() from inside and outside of for loop I get two different values"_? --- Ok, then why do you expect them to be the same? — evolutionxbox, Jan 18 '22 at 08:05
if i will use let how to access it from outside of for loop?? — swapnil agrawal, Jan 18 '22 at 08:05
@swapnilagrawal - You're repeatedly assigning to the same variable, naturally the last assignment wins. If you want to retain multiple values, you have to use something that can hold multiple values (an array, an object, a Map, a Set, ...). — T.J. Crowder, Jan 18 '22 at 08:05
@johnSmith - Heh, actually that's the one part that seems right to me. :-) — T.J. Crowder, Jan 18 '22 at 08:07
@T.J Crowder How Sir ? I am new to programming and trying to find out from last two days — swapnil agrawal, Jan 18 '22 at 08:08
@ceving - Yes, I know. I deleted the comment almost immediately. I'd just misread the code. — T.J. Crowder, Jan 18 '22 at 08:08
@swapnilagrawal - I suggest working through a good beginner's tutorial or book. Stack Overflow's Q&A format isn't designed for tutorials or individual tuition. — T.J. Crowder, Jan 18 '22 at 08:10
@T.J Crowder Sir, If you will tell, someone will also get to learn from this. — swapnil agrawal, Jan 18 '22 at 08:18
Search the internet for *javascript tutorial* or *javascript documentation*. Look at everything on the first page and find one that suits you. — Peter Krebs, Jan 18 '22 at 08:21

score 0 · Answer 1 · answered Jan 18 '22 at 08:50

I'm going to assume that UpdatedCategory is an object (if it's an array, please see my answer here for what to use instead of for-in to loop through it).

The basic problem with that code is that you're assigning to the same variable over and over. The reason it's the same variable is that var doesn't have block scope, so the var part of var categoryProductid = actual.id; is completely ignored (and similar for var PPProducttitle = actual.title;). Instead, you're reusing the variables you declared prior to the for loop.

A variable can only hold one value, so when you assign a new value to it, it no longer holds the old value.

If you want to hold multiple values with a variable, you can assign a container to it that can hold multiple values, such as an array, an object, a Map, or a Set.

You haven't said what end result you want, but here's an example that creates two arrays and fills them with the id and title of the products from UpdatedCategory:

// Again, I'm assuming `UpdatedCategory` is an object:
const UpdatedCategory = {
    a: {
        id: 1,
        title: "a",
    },
    b: {
        id: 2,
        title: "b",
    },
    c: {
        id: 3,
        title: "c",
    },
};

// `[]` creates a new empty array.
// We can use `const` to declare these because we never change their
// value (they only ever refer to a single array), but you could use
// `let` if you preferred. Don't use `var` in new code, it's deprecated.
// Note: I've renamed these slightly to:
// 1. Stick to standard naming conventions
//     * Initial capitals are used primarily for constructor functions
//     * Variables referring to arrays are generally plurals
// 2. Be consistent in capitalization
const categoryProductIds = [];
const ppProductTitles = [];

for (var key in UpdatedCategory) {
    // Get this property value
    const actual = UpdatedCategory[key];

    // Push the `id` and `title` into the relevant arrays
    categoryProductIds.push(actual.id);
    ppProductTitles.push(actual.title);
}

// Show the contents of the arrays
console.log(ppProductTitles);
console.log(categoryProductIds);

for loop gives only last value in javascript

1 Answers1