co3496558でやってたピラミッド作る問題

pyramid.js

function createPyramid(height){
  return Array.from({length: height}, (v,k) => k+1)
  .map(r => ' '.repeat(height-r).concat('*'.repeat(r*2-1)))
  .join('\n');
}

console.log(createPyramid(10));

for文で書くとこうかな

function createPyramid(height) {
  var pyramid = [];
  for(var i=1; i<=height; i++) {
    pyramid.push( ' '.repeat(height-i) + '*'.repeat(i*2-1) );
  }
  return pyramid.join('\n');
}