1. const shape = {
radius: 10,
diameter() {
return this.radius * 2;
},
perimeter: () => 2 * Math.PI * this.radius,
};
console.log(shape.diameter());//
console.log(shape.perimeter());//
20
NaN
let obj = {
x: 2,
getX: function() {
setTimeout(() => console.log('a'), 0);//
new Promise( res => res(1)).then(v => console.log(v));//
setTimeout(() => console.log('b'), 0);//
}
}
obj.getX();
o/p :- promise , first SetTimeOut and then second SetTimeOut :- 1,a,b
var a = 10;
function abc(){
console.log(a);//
var a = 20;
console.log(a);//
}
console.log(a);//
abc();//
10
10, error can not redeclare a as it is global scoped
10
undefined
20
var a = {'key': 100};
var b = []
b[a] = 90;
console.log(b);//
[object Object]: 90
var a = 50;
var b = { name : 'abc' };
function abc(a,b){
console.log(a,b);//
b.name = 'cde';
console.log(a,b);//
}
abc();//
abc(a,b);//
console.log(a,b);//
50, { name : 'abc' } -> 50, { name : ‘c’de }
50, { name : 'abc' } -> 50, { name : ‘c’de }
50, { name : 'abc' }
undefined undefined
undefined undefined
50 { name: 'abc' }
50 { name: 'cde' }
50 { name: 'cde' }
function foo() {
let a = b = 0;
a++;
return a;
}
foo();
console.log(typeof a); //
console.log(typeof b); //
1
undefined
number
let a =10
{
var a = 20
}
console.log(a);//
SyntaxError: Identifier 'a' has already been declared
