TypeScript any or unknown?

What is the difference between 'unknown' and 'any' in TypeScript?

'unknown' is more type-safe and contributes to TypeScript control flow-based type analysis. This means you can't assign 'unknown' type to any other variable type without type checking.

Here example with unknown

function testFunc(nameOfVar: unknown) { 
    if (typeof nameOfVar == 'string') {
        const anotherStringVar: string = nameOfVar;
    }
}

Example with any

function testFunc(nameOfVar: any) { 
    const anotherStringVar: string = nameOfVar;
}

'Any' type literally could be assigned to any value.

When you should use 'unknown'?

'unknown' requires your code to be more predictable. Because you clearly assign a value if a type is definitely correct.
unknown is recommended because it provides safer typing — you have to use type assertion or narrow it to a specific type.

Can I use 'any' instead of 'unknown'?

Yes, you can but then TypeScript won't control strictly your assignments. This is a bit risky because your code can't guarantee that called or assigned variable has the correct type.

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