With the following code:
var x:boolean = true;
x &= false;
Results in error TS2447: The '&=' operator is not allowed for boolean types. Consider using '&&' instead.
I've looked around but can't find a reason why, there's a PR to make the error what it is: https://github.com/Microsoft/TypeScript/issues/712 but still can't find the underlying reason for it.
Can someone clarify?
Typescript 4.0+ now supports logical assignment. Here is the online example.
type Bool = boolean | null | undefined;
let x: Bool = true;
x &&= false; // => false
x &&= null; // => null
x &&= undefined; // => undefined
let y: Bool = false;
y &&= true; // => false
y &&= null; // => false
y &&= undefined; // => false
Which is equivalent to
type Bool = boolean | null | undefined;
let x: Bool = true;
x && x = false; // => false
x && x = null; // => null
x && x = undefined; // => undefined
let y: Bool = false;
y && y = true; // => false
y && y = null; // => false
y && y = undefined; // => false