Greetings! I am just starting to learn JavaScript and TypeScript
I have a question about the code snippet below
What does the pipe symbol (|) signify?
Also, why is null = null being used here?
let element: HTMLElement | null = null;
Greetings! I am just starting to learn JavaScript and TypeScript
I have a question about the code snippet below
What does the pipe symbol (|) signify?
Also, why is null = null being used here?
let element: HTMLElement | null = null;
let item: HTMLElement | null = null;
// Similar to
let item: (HTMLElement | null) = null;
| indicates a union type, allowing the variable to be any of the listed types.
This snippet implies:
item,HTMLElement OR null,null.Describing a concept known as a union type.
In this scenario, the variable element can hold either an object of type HTMLElement or simply be set to null.
It's important to understand that HTMLElement | null represents the type, while = null signifies the assignment - it is not null = null.
To express this more clearly:
type PossibleHTMLElement = HTMLElement | null;
let element: PossibleHTMLElement = null;
This alternative formulation may enhance comprehension.
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