Discussion on: The Power of Union and Type Guard in TypeScript 🤯

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Replies for: If we have interface A { name: string; id: number; } interface B { uni: string; age: number; } type ArrType = Array<A | B> ...

function isA(v): v is A {
  return "name" in v && "id" in v;
}

function isB(v): v is B {
  return "uni" in v && "age" in v;
}
arr.map(item => {
  if(isA(item)) {
    console.log(item.id, item.name);
  }
})