Learn how to check for undefined, null, or empty strings in JavaScript. Use conditional statements and type-checking functions to determine whether a variable has a… Read More »JavaScript checks undefined or null or empty
If you’re experiencing a JavaScript function that returns undefined instead of the expected value, there may be several reasons behind this. These reasons include not… Read More »JavaScript function returns undefined instead of value
In JavaScript, “undefined” is a primitive type that represents a variable that has been declared but not assigned a value. It is also used as… Read More »Type of undefined in JavaScript
With the Nullish Coalescing Operator, you can set a default value if a value is null or undefined in JavaScript. However, you should be aware… Read More »JavaScript default value if undefined | Code
You will get this error (message in the log) object length undefined in JavaScript if you use the length property in an Object. Use Object.keys(yourObject).length… Read More »JavaScript object length undefined | Solution
Objects don’t have a length property, that way most time developers get JavaScript array length undefined error. A simple solution is, if you know you… Read More »JavaScript array length undefined | Code
Use length property with the isArray() method to check an array is undefined in JavaScript. Or do the check for undefined first, array empty or… Read More »JavaScript array is undefined | Example code
The undefined value is a condition where an expression does not have a correct value. JavaScript undefined property indicates that a variable has not been… Read More »JavaScript undefined property | Variable value
The difference between undefined and null is undefined means a variable has been declared but has not yet been assigned a value, where null is… Read More »Difference between undefined and null in JavaScript | Example code
In JavaScript, you can use the typeof operator to check if a variable is undefined. If a variable is not initialized, its value will also… Read More »JavaScript check if undefined | Example code