test.ts•781 B
type Baz = { qux: string } | undefined;
const bar = {
baz: {
qux: "quux",
} as Baz,
};
console.log(bar);
console.log("bar.baz", bar.baz);
console.log("bar.baz.qux", bar.baz?.qux);
function setRandom(): Baz {
return Math.random() > 0.5 ? { qux: "random" } : undefined;
}
bar.baz = setRandom();
console.log("bar.baz.qux", bar.baz?.qux);
type FooString = { foo?: string };
console.log();
function dump(fooString: FooString) {
if (fooString.foo) {
console.log(fooString.foo);
} else {
console.log("NOPE");
}
}
const foo: FooString = { foo: "bar" };
dump(foo);
const foo1 = { foo: undefined } as FooString;
dump(foo1);
const foo2 = { foo: "" } as FooString;
dump(foo2);
const hello = [1, 2];
console.log([3].concat(hello));