Чому функція в js повертає undefined?
Why is my JavaScript function undefined?
A variable that has not been assigned a value is of type undefined . A method or statement also returns undefined if the variable that is being evaluated does not have an assigned value. A function returns undefined if a value was not returned .
What is undefined in JS?
Undefined is a type of Data type in JavaScript. It is a primitive value undefined, when a variable is declared and not initialized or not assigned with any value. By default, the variable was stored with an Undefined value.
How to solve an undefined error?
Yes, you can use a try… catch block to handle undefined variable errors. However, it's generally better to prevent such errors by properly declaring and initializing variables, using the typeof operator, or using default parameters.
How to avoid undefined error in JS?
To prevent undefined variable errors in JavaScript, consider the following tips:
- Always declare variables using var, let, or const before using them.
- Ensure variables are properly initialized with a value before accessing them.
- Use meaningful variable names to avoid accidental naming conflicts.
When I try to execute the script I get an error in my console log which says this: ReferenceError: start is not defined . Where have I gone …
A function returns undefined if a value was not returned . Note: While you can use undefined as an identifier (variable name) in any scope other …
undefined is JavaScript’s way of telling you: “Hey, something’s missing here”. It might be a missing property, an uninitialized variable, a …