This will return a string with the type of 123, which, in this case, will be 'number'. For example, to find the type of 123, we would write - typeof 123 Description The following table summarizes the possible return values of typeof. 54 Answers Sorted by: 1 2 Next 2362 If typeof yourVariable object, its an object or null. Try it Syntax typeof operand Parameters operand An expression representing the object or primitive whose type is to be returned. Because, function also an object, that's why it's there. The typeof operator returns a string indicating the type of the operand's value. In isDerivedObject function, it checks for the o is a function. If you need a more rigorous check as to check whether an object is a plain old JavaScript object (or POJO for short), you can use the below function.The typeof operator in JavaScript evaluates and returns a string with the data type of an operand. After typeof o 'object' check, toString.call (o) is a great method to check whether o is an object, a derived object like Array, Date or a function. The typeof operator is useful because it is an easy way to check the type of a variable in your code. You can use this to validate function parameters or check if variables are defined. This check will allow any object through, including objects that are instances of classes. typeof is a JavaScript keyword that will return the type of a variable when you call it. The Object type, however, describes functionality that available on all objects. The first option is to hardcode an if statement as follows: let test = įn instanceof Object // true Checking for POJOs The TypeScript object type represents any value that is not a primitive value.

To handle these cases, you have a couple options. Objects can be a bit frustrating when using the typeof operator because typeof returns 'object' for both null and.

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