JavaScript 中条件语句的快捷方式

Question

I do have the following variable:

var text = getValue();

getValue() - can be empty, thus text === undefined, can be === "Example" but also can be === "Hello World.

I want to check two things: 1. if text !== undefined AND if text === "Hello World"

Method for achieving it:

if(text !== undefined && text === "Hello World")

Issue : The text variable is typed in twice for two comparisions.

Question : How to check two things(undefined, Hello World) but using text once?

EDIT : I did a mistake with the example, check the new variable text; Thank you!

Answer 1

text === "Hello World"

implies that it is not undefined , so it is the only condition needed.

if (text === "Hello World") { ...

---

Additional info

To check if a string has content, you can check:

if (text) { ...

It means the same as:

if (text !== undefined && text !== null && text !== '') { ...

Answer 2

Above answer works, but for more nested property check, use Optional chaining