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Comment by brett40324 | Hacker News Reader

> In TS, you'd have to type every function signature to get the same level of confidence.

I don't disagree, but isn't this the point? That by typing every function you can reliably have confidence in parameter types and return value types, and if your program is able to throw a type error on build, then it should and alert the developer that they're not logically correct in their implementation.

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My point is mostly that you can get away with explicitly typing less things in flow and still get similar levels of coverage. For example, consider this example:

    export function formatTime(time: Date) {
      return digitize(time.getHours()) + ':' + digitize(time.getMinutes());
    }
    function digitize(n) {
      return ('0' + n.toStirng()).substring(-2);
    }

Just a single type declaration is enough to let Flow catch the typo here. In TS, you'd also have to write the argument types for `digitize`. Importantly, if you wanted to explicitly add arg types for `digitize` w/ Flow, your editor can tell you what they are supposed to be.

FLow seem to be better at inferring types. example:

    function foo(n) {
          return n*2;
    }
    
    foo("bar");

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