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JavaScript Coding Question – 13

const Person = {
    firstName: 'abc',
    lastName: 'xyz',
    age: 50
};

const result = Object.entries(Person);

console.log(result);

Output:

[
  [ 'firstName', 'abc' ],
  [ 'lastName', 'xyz' ],
  [ 'age', 50 ]
]

Above code will convert the properties of the Person object into an array of key-value pairs using Object.entries().
Object.entries(Person) : takes each property of the Person object and convert it into an array, where each element is a [key, value] pair.

let x = 5;
let y = 7;
let z = 1;

let result = x + y;
result += x;
result -=z;

console.log(result);

Output:

16

const data = {
    name: "javascript",
    name: "React"
}

const result = data.name.at(-2);

console.log(result);

Output:

c

In JavaScript Objects if we have duplicate property names, only the last definition will be retained. So in this case data.name will be "React".
.at(-2) will give the second character from the last which is ‘c’ in this case.

const obj1 = {a: 1, b: 2};
const obj2 = {c: 2, d:4, e:5};

Object.assign(obj2, obj1);

const result = Object.keys(obj2);

console.log(result)

Output:

[ 'c', 'd', 'e', 'a', 'b' ]

Object.assign(obj2, obj1) : merges obj1 properties into obj2.( adding the properties from obj1 into obj2 directly.)
Object.keys(obj2): Gets the keys of the modified obj2.
Since obj1’s keys (a and b) are added to obj2, result includes all keys from both objects.

const expr1 = (null <= 0);
const expr2 = ('' == false);

const result = (expr1 === expr2);

console.log(result)

Output:

true

expr1 = (null <= 0): In JavaScript, null is converted to ‘0’ when compared with number which makes null <= 0 evaluate to true.
expr2 = ('' == false): The == operator performs type coercion. An empty string ('') is coerced to a number, which results in 0. Thus, '' == false evaluates to true because false is also coerced to 0.
result = (expr1 === expr2): Since both expr1 and expr2 are true, the comparison true === true evaluates to true.