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object-method-cheats.js
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object-method-cheats.js
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// Accessing Object properties using dot notation
const apple = {
color: 'Green',
price: {
bulk: '$3/kg',
smallQty: '$4/kg'
}
};
console.log(apple.color); // 'Green'
console.log(apple.price.bulk); // '$3/kg'
// Accessing non-existent properties
const classElection = {
date: 'January 12'
};
console.log(classElection.place); // undefined
// Example showing Objects are mutable, even when declared as 'const'
const student = {
name: 'Sheldon',
score: 100,
grade: 'A',
};
console.log(student)
// { name: 'Sheldon', score: 100, grade: 'A' }
delete student.score
student.grade = 'F'
console.log(student)
// { name: 'Sheldon', grade: 'F' }
student = {}
// TypeError: Assignment to constant variable.
// Example for...in loop
let mobile = {
brand: 'Samsung',
model: 'Galaxy Note 9'
};
for (let key in mobile) {
console.log(`${key}: ${mobile[key]}`);
};
// Delete operator
const person = {
firstName: "Matilda",
age: 27,
hobby: "knitting",
goal: "learning JavaScript"
};
delete person.hobby; // or delete person[hobby];
console.log(person);
/*
{
firstName: "Matilda"
age: 27
goal: "learning JavaScript"
}
*/