JavaScript: Get the data type
JavaScript Function: Exercise-9 with Solution
Write a JavaScript function that accepts an argument and returns the type.
Note : There are six possible values that typeof returns: object, boolean, function, number, string, and undefined.
Sample Solution-1:
JavaScript Code:
// Define a function named detect_data_type that determines the data type of the given value
function detect_data_type(value) {
// Define an array of data types to check against: Function, RegExp, Number, String, Boolean, Object
var dtypes = [Function, RegExp, Number, String, Boolean, Object], x, len;
// Check if the value is an object or a function
if (typeof value === "object" || typeof value === "function") {
// Iterate through the array of data types
for (x = 0, len = dtypes.length; x < len; x++) {
// If the value is an instance of the current data type, return the data type
if (value instanceof dtypes[x]) {
return dtypes[x];
}
}
}
// If the value is not an object or function, return its typeof value
return typeof value;
}
// Log the result of calling detect_data_type with the input value 12 to the console
console.log(detect_data_type(12));
// Log the result of calling detect_data_type with the input value 'w3resource' to the console
console.log(detect_data_type('w3resource'));
// Log the result of calling detect_data_type with the input value false to the console
console.log(detect_data_type(false));
Output:
number string boolean
Flowchart:
Live Demo:
See the Pen JavaScript -Check a number is prime or not-function-ex- 8 by w3resource (@w3resource) on CodePen.
Sample Solution-2:
JavaScript Code:
function getType(value) {
const typeString = Object.prototype.toString.call(value);
// Extract the type from the string, removing brackets and the "object " prefix
return typeString.slice(8, -1).toLowerCase();
}
// Example usage:
console.log(getType("Hello")); // Output: string
console.log(getType(42)); // Output: number
console.log(getType(true)); // Output: boolean
console.log(getType(null)); // Output: null
console.log(getType(undefined));// Output: undefined
console.log(getType([])); // Output: array
console.log(getType({})); // Output: object
Output:
string number boolean null undefined array object
Flowchart:
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Previous: Write a JavaScript function that accepts a number as a parameter and check the number is prime or not.
Next: Write a JavaScript function which returns the n rows by n columns identity matrix.
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