type Node = {
value: Value;
next: Node
} | null;
function output(n: Node) {
function isEmpty() {
return n === null;
}
// n === null
if (isEmpty()) {
console.log("empty");
} else {
// nnull
n.next = {value: "yo", next: null};
}
} this is just a simple example, but most of the time we write a lot of logic in isEmpty , but these logic usually avoid n = null , so the language in else should pass. How to change this?
function isEmpty(n: Node): n is null {
return n === null;
}
// n === null
if (isEmpty(n)) {
console.log('empty');
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