What does open={Boolean(anchor)} mean for a MUI component

January 16, 2023

Working with some legacy code where a MUI menu has been defined within a React component written with TypeScript as below:

interface Props {
anchor: HTMLButtonElement | null;
}
...
<Menu
  id="order-menu"
  anchorEl={anchor}
  open={Boolean(anchor)}
  onClose={onClose}
>
...
</Menu>

Not sure if I understand the meaning or purpose of the syntax open={Boolean(anchor)}. It would be kind if anyone can explain a bit.

>Solution :

Boolean(...) returns a boolean value, i.e. true or false.

If anchor is truthy (i.e. there’s an object), then Boolean(anchor) returns true.

If anchor is falsy (e.g. it’s null), then Boolean(anchor) returns false.

In your code snippet, it means that Menu prop open will be set to true if anchor is an object, and false if there’s no object (if anchor is null).