TypeScript

by Financial Modeling Prep

HTML

<div id="app"></div>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#app {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  transition: all 0.2s;
  text-align: center;
}

TypeScript

let add = (arr: Array<number> , elem: number) => {
  
  return arr.push(elem);
}


let add = (arr: Array<string> , elem: string) => {
  
  return arr.push(elem);
}


add([1,2,3], 4); // ok
add([1,2,'2',4], 'a'); // error
add(['1','2'], '3'); // ok
add(['1','2'], 3); // error 
add([[2], [2]], 3); // error