Introduction
This article covers the following tech skills:
In this lab, we will explore the concept of data types in JavaScript. We will learn how to use the getType
function to determine the native type of any given value, whether it is undefined
, null
, or an instance of a constructor. By the end of the lab, you will have a solid understanding of how to work with different data types in JavaScript.
Function to Get Type of Value
To get the type of a value, use the following function:
const getType = (v) => {
if (v === undefined) {
return "undefined";
}
if (v === null) {
return "null";
}
return v.constructor.name;
};
- The function returns
'undefined'
or'null'
if the value isundefined
ornull
. - Otherwise, it returns the name of the constructor by using
Object.prototype.constructor
andFunction.prototype.name
.
Example usage:
getType(new Set([1, 2, 3])); // 'Set'
Summary
Congratulations! You have completed the Type of Value lab. You can practice more labs in LabEx to improve your skills.
π Practice Now: Type of Value
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Top comments (2)
But wait:
getType(+("NaN")) => Number
?getType(1/0) => Number
?This small module may be more useful.
You've missed BigInt from the primitive types