flow/tests/binary/in.js at main · dominictobias/flow

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let tests = [

// objects on RHS

function() {

('foo' in {});

('foo' in { foo: null });

(0 in {});

(0 in { "0": null });

// arrays on RHS

function() {

('foo' in ([]: Array<string>));

(0 in ([]: Array<string>));

('length' in ([]: Array<string>));

// primitive classes on RHS

function() {

('foo' in new String('bar'));

('foo' in new Number(123));

// primitives on RHS

function() {

('foo' in 123); // error

('foo' in 'bar'); // error

('foo' in void 0); // error

('foo' in null); // error

// bogus stuff on LHS

function() {

(null in {}); // error

(void 0 in {}); // error

({} in {}); // error

(([]: Array<string>) in {}); // error

(false in ([]: Array<string>)); // error

// in predicates

function() {

if ('foo' in 123) {} // error

if (!'foo' in {}) {} // error, !'foo' is a boolean

if (!('foo' in {})) {}

// annotations on RHS

function(x: Object, y: mixed) {

('foo' in x); // ok

('foo' in y); // error

]