23 lines
532 B
JavaScript
23 lines
532 B
JavaScript
// @flow
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declare function my_filter<T, P: $Pred<1>>(v: Array<T>, cb: P): Array<$Refine<T,P,1>>;
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// Sanity check A: filtering the wrong type
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declare var a: Array<mixed>;
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const b = my_filter(a, is_string);
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(b: Array<number>);
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// Sanity check B: Passing non-predicate function to filter
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declare var c: Array<mixed>;
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const d = my_filter(c, is_string_regular);
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(d: Array<string>);
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function is_string(x): boolean %checks {
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return typeof x === "string";
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}
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function is_string_regular(x): boolean {
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return typeof x === "string";
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}
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