TypeScript Problem Solving Questions

console.clear();

function Foo() {
 this.bar = 10;
}
Foo.prototype.bar = 42;
var foo = new Foo();
console.log("1:", foo.bar);
delete foo.bar;
console.log("1:", foo.bar);


// OUTPUT OF CODE
// [LOG]: "1:", 10 
// [LOG]: "1:", 42 

const x = [1,2,3];
x[-1] = -1;
console.log(x[x.indexOf(10000)]);

// OUTPUT OF CODE
// [LOG]: -1 





let index1:number = 1;
function tutest() {
let index2:number = 2;
if(index2 > index1) {
let index3:number = 3;
 index3++;
 }


 while(index1 < index2) {
let index4:number = 4;
 index1++;
 }

 console.log(index1);
 console.log(index2);
 console.log(index3);
 console.log(index4);

}
tutest();

// OUTPUT OF CODE
//[LOG]: 2 
//[LOG]: 2 
//[ERR]: "Executed JavaScript Failed:" 
//[ERR]: index3 is not defined 

use https://www.typescriptlang.org/play/?#code/Q