Christopher Chedeau
cf45afba61
- This brings in the flow test suite that contains a ton of JavaScript parsing edge cases - This creates snapshot tests using the pretty printer for all of them - If uncomment `RUN_AST_TESTS` line in `tests/run_specs.js`, it checks ast(pretty_print(x)) == ast(x). Right now, "178 failed, 197 passed, 375 of 377 total". So half of the tests are not passing, most of them are crashes and many of the rest are subtle issues.
19 lines
540 B
JavaScript
19 lines
540 B
JavaScript
// @flow
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declare function is_string(x: mixed): boolean %checks(typeof x === "string");
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declare function is_number(x: mixed): boolean %checks(typeof x === "number");
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// Feature check:
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function foo(x: string | Array<string>): string {
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if (is_string(x)) {
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// The use of `is_string` as a conditional check
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// should guarantee the narrowing of the type of `x`
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// to string.
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return x;
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} else {
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// Accordingly the negation of the above check
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// guarantees that `x` here is an Array<string>
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return x.join();
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}
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}
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