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0 pointsepolanski3y ago0 comments

But the previous example isn't that case.

if (c.type === 'a') { /* c is of type A here */ }

This is dynamic typing, this code is checked at runtime, and it's leveraged statically.

0 comments

xg153y ago

Yes, that's correct. In the GP example, c was const, so the type can be determined at compile time.

I was writing TypeScript, where const just means the variable is not reassigned. For instance this is valid:

    const c: C = Math.random() < 0.5 ? { type: 'a' } : { type: 'b' }.

xg153y ago

Ah, I'm sorry. You're right of course!

j / k navigate · click thread line to collapse

0 pointsepolanski3y ago0 comments

But the previous example isn't that case.

if (c.type === 'a') { /* c is of type A here */ }

This is dynamic typing, this code is checked at runtime, and it's leveraged statically.

xg153y ago

Yes, that's correct. In the GP example, c was const, so the type can be determined at compile time.

I was writing TypeScript, where const just means the variable is not reassigned. For instance this is valid:

    const c: C = Math.random() < 0.5 ? { type: 'a' } : { type: 'b' }.

xg153y ago

Ah, I'm sorry. You're right of course!

j / k navigate · click thread line to collapse