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In JavaScript, a TypeError is an object that represents an error as a result of performing an operation that cannot be performed, usually because a value in an operation is not of the expected type.
But what is a guy? According to the latest version of the JavaScript specification, ECMAScript, there are nine types of data and structure. Six of which (sometimes seven if counting null) are primitive data types, namely string, number, large, boolean, undefined, and symbol. Before we understand why TypeErrors fires during an operation, let’s take a look at our nine types in JavaScript. If we are ever in a position where we don’t know how to classify a type, we can use the typeof operator.
- undefined: a type of value that is automatically defined in new declared variables. We often get an undefined type error value when we forget to set or add a value to our variable.
- Boolean: logical data type containing only true or false values.
- Number:. Numeric data type
- String:. sequence of characters in grave, single or double accents
- BigInt: Data type digits sometimes known as bignum in other programming languages.
- Symbol: value representing a unique identifier created by calling the Symbol function.
- Object: a structural type and almost anything " new " that the keyword is capable of creating, such as an array, object, map, device, etc.
- Function: another non-data structure which is a snippet that can be called from other parts of code
- null:. usually an intentional value representing an object or an address that does not exist.
The most common JavaScript TypeErrors and how to fix them
TypeErrors can be thrown when trying to change a value that cannot be changed or when l use of a value inappropriately. This can also happen when an argument is passed to a function that is incompatible with the type expected by the function or operator within the function.
