[typescript]type never

Tue Feb 11

typescript

Author：Noritaka

function erro(message: string): never {
  throw new Error(message);
}
console.log(erro('This is an error'));

function getSizeName(size: 's' | 'm' | 'l') {
  switch (size) {
    case 's': return 'small'
    case 'm': return 'medium'
    case 'l': return 'large'
    default: return size satisfies never
  }
}

function getSizeName2(size: 's' | 'm' | 'l' | 'xl') {
  switch (size) {
    case 's': return 'small'
    case 'm': return 'medium'
    case 'l': return 'large'
    default: return size satisfies never
  }
}