编辑代码

interface LabelledValue {
  label: string;
}

function printLabel(labelledObj: LabelledValue) {
  console.log(labelledObj.label);
}

function isNumber(x: any): x is number {
  return typeof x === "number"
}

console.log(isNumber(1))

let myObj = {size: 10, label: "Size 10 Object"};
printLabel(myObj);