Contoh 1: Menggunakan instanceof Operator
// program to check if a variable is of function type
function testVariable(variable) {
if(variable instanceof Function) {
console.log('The variable is of function type');
}
else {
console.log('The variable is not of function type');
}
}
const count = true;
const x = function() {
console.log('hello')
};
testVariable(count);
testVariable(x);
Keluaran
The variable is not of function type The variable is of function type
Pada program di atas, instanceof
operator digunakan untuk memeriksa jenis variabel.
Contoh 2: Menggunakan Operator typeof
// program to check if a variable is of function type
function testVariable(variable) {
if(typeof variable === 'function') {
console.log('The variable is of function type');
}
else {
console.log('The variable is not of function type');
}
}
const count = true;
const x = function() {
console.log('hello')
};
testVariable(count);
testVariable(x);
Keluaran
The variable is not of function type The variable is of function type
Pada program di atas, typeof
operator digunakan dengan ketat sama dengan ===
operator untuk memeriksa jenis variabel.
Itu typeof
operator memberikan tipe data variabel. ===
memeriksa apakah variabel sama dalam hal nilai serta tipe data.
Contoh 3: Menggunakan Metode Object.prototype.toString.call()
// program to check if a variable is of function type
function testVariable(variable) {
if(Object.prototype.toString.call(variable) == '[object Function]') {
console.log('The variable is of function type');
}
else {
console.log('The variable is not of function type');
}
}
const count = true;
const x = function() {
console.log('hello')
};
testVariable(count);
testVariable(x);
Keluaran
The variable is not of function type The variable is of function type
Itu Object.prototype.toString.call()
metode mengembalikan string yang menentukan tipe objek.