NEW - Check out our NEW program SheCodes Bootcamp - and become a developer in just 4 months!
More
Learn more
what is "Identifier has already been declared" ?
This error message typically occurs when you try to declare a variable or function with a name that has already been used in the same scope. In other words, you are trying to assign a value or define something using a name that is already being used elsewhere in your code.
Here's an example in JavaScript:
javascript Copy code
let x = 10;
let x = 20; // Error: Identifier 'x' has already been declared
console.log(x);
In this example, we first declare a variable x and assign it a value of 10. Then, we try to declare another variable x with a different value of 20. This will result in an error because x has already been declared in the same scope.
To fix this error, you should use a different name for the variable or function, or remove the duplicate declaration if it's not needed. For example:
javascript Copy code
let x = 10;
let y = 20;
console.log(x + y);
In the corrected code above, we use the variable name y instead of x to avoid the "Identifier has already been declared" error.
what is key in JS?
In JavaScript, a key refers to a unique identifier used to access values in an object. An object in JavaScript is a collection of key-value pairs, where the key is the identifier and the value is the associated data. Keys are used to access and manipulate the values stored in the object.
Here's an example of an object in JavaScript with keys:
javascript Copy code
let person = {
name: 'John',
age: 25,
occupation: 'Engineer'
};
In this example, the keys are name, age, and occupation. These keys can be used to access the corresponding values:
javascript Copy code
console.log(person.name); // Output: John
console.log(person.age); // Output: 25
console.log(person.occupation); // Output: Engineer
You can also use keys to modify or add new values to an object:
javascript Copy code
person.age = 26;
person.city = 'New York';
console.log(person.age); // Output: 26
console.log(person.city); // Output: New York
Remember that keys in JavaScript are case-sensitive, so name is different from Name.
👩💻 What is different with this coe? : const person = { name : "Jana", age : 37 }; for ( let key in person) console.log(key, person[key]);
The code you provided creates an object named person with two properties: name and age. Here's a breakdown of what the code does:
javascript Copy code
const person = {
name: "Jana",
age: 37
};
This code declares a constant variable person and assigns it an object with the properties name and age. The name property has the value "Jana", and the age property has the value 37. The const keyword ensures that the person variable cannot be reassigned to a different object.
javascript Copy code
for (let key in person) {
console.log(key, person[key]);
}
This code uses a for...in loop to iterate over each key in the person object. The key variable represents each key in the loop, and person[key] accesses the corresponding value for that key.
During each iteration of the loop, the code logs the key and person[key] to the console. This means that it will print the key-value pairs of the person object:
Output:
code Copy code
name Jana
age 37
The output shows the keys (name and age) followed by the corresponding values ("Jana" and 37).
How to avoid case sensitive in java script
JavaScript is a case-sensitive language. To avoid case-sensitive errors, use the same case for all references to the same identifier. For example, userName and username are not the same in JavaScript.
In order to avoid confusion and potential errors, you can use the toUpperCase() or toLowerCase() methods which both take a string as argument and convert it to upper or lower case, respectively. For example:
javascript Copy code
let myString = "Banana";
let newString = myString.toUpperCase();
console.log(newString); // Outputs: BANANA
in Javascript could you please add a identifier"enfant" to THE CHILD CLASS "search-section no-border" and then add a css to the class enfant : display:none;
javascript Copy code
var childClass = document.querySelector('.search-section.no-border');
childClass.classList.add('enfant');
document.querySelector('.enfant').style.display = 'none';
If you have any other questions, you can easily reach out to us here
AI stands for Artificial Intelligence. AI bots are able to learn from conversations with users and expand their knowledge this way.
SheCodes Athena will help you with technical questions about your code using artificial intelligence to find the answer. Imagine a super powerful human who has memorized everything on the internet and can access that knowledge in a matter of seconds. 🤯
SheCodes Athena can answer most coding-related questions, even complicated ones! It can even find bugs in your code and tell you how to fix them in just a few seconds. Impressive, right?
Just remember we're still in testing mode so the AI may return strange or incorrect replies. Feel free to message us if this happens!
SheCodes Athena can only reply to coding-related technical questions. The same type of questions you would ask in the channels on Slack.
For questions that are not coding-related, write us here 😃
You should treat Athena like a SheCodes team member, so always be polite! 😊 Ask your questions as detailed as possible, just like you would do on Slack.
Here are some examples:
- Prettier isn't working on my VS Code. How do I fix this?
- How do I make bullet points with different colors using the list element?
- My code in Codesandbox is having some issues. Can you please tell me what the issue is? [Include the link to your Codesandbox]
For now, SheCodes Athena is limited to 5 questions per day for each student.
In that case, you can either ask SheCodes Athena a follow-up question, or you can post on the designated weekly channel on Slack!
Our technical assistants are still available on Slack and are always happy to help! 😍💪
Remember, questions are limited to 1000 characters.
- If you're working with an HTML file: Post a snippet of your code related to the issue you're having (just copy the code and paste it into the question box).
- If you're working with Codesandbox: Good news, you can just post the link to your Codesandbox and the AI Assistant will be able to view your code.
- If you have a longer question that would require an entire HTML file or more than 1000 characters, post it in the designated weekly channels on Slack! 😃
Athena was the Greek goddess of wisdom, among other elements. She received her name from the city of Athens, which she is known for protecting.
Much like the goddess Athena, SheCodes Athena is also incredibly wise and can solve complicated coding puzzles in a matter of seconds! 😍
Not likely. AI can automate tasks and make developers' jobs more efficient but it can't fully replace the human ability to deal with complex software. And AI will still require human developers to supervise and improve it further.
So developers may see their tasks change but they won't be replaced by AI. 👩💻🤝💻