Hollow Triangle Star Pattern

// Hollow Triangle Star Pattern........

function HollowTrianglePattern(n){
let str=''
for(let i=0;i<n;i++){
for(let j=0;j<=i;j++){
if(j==0 ||j==i || i==n-1){
str+='*'
}else{
str+=' '
}

}
str+='\n'

}
return str
}

console.log(HollowTrianglePattern(6))