···204205What does that mean in practice?
206207-Suppose that you [wanted to](https://stackoverflow.com/questions/39540156/typescript-number-must-be-less-than-1-and-greater-than-0) write a function that takes a number strictly between `0` and `1`. In TypeScript, you can't do much better than throwing a runtime error:
208209```js
210function someFunction(x: number) {
···204205What does that mean in practice?
206207+Suppose that you [wanted to](https://stackoverflow.com/questions/39540156/typescript-number-must-be-less-than-1-and-greater-than-0) write a function that takes a number strictly between `0` and `1`. In TypeScript, you can't do [much](https://gist.github.com/gaearon/966446d27de88ba4d4806a9a5b291d0a) better than throwing a runtime error:
208209```js
210function someFunction(x: number) {