Function getIterationTypesOfIteratorResult

test/fixtures/snapshot/typescript.js:83449–83480

* Gets the *yield* and *return* types of an `IteratorResult`-like type. * * If we are unable to determine a *yield* or a *return* type, `noIterationTypes` is * returned to indicate to the caller that it should handle the error. Otherwise, an * `IterationTypes` rec

(type)

         * `IterationTypes` record is returned.
         */
        function getIterationTypesOfIteratorResult(type) {
            if (isTypeAny(type)) {
                return anyIterationTypes;
            }
            var cachedTypes = getCachedIterationTypes(type, "iterationTypesOfIteratorResult");
            if (cachedTypes) {
                return cachedTypes;
            }
            // As an optimization, if the type is an instantiation of one of the global `IteratorYieldResult<T>`
            // or `IteratorReturnResult<TReturn>` types, then just grab its type argument.
            if (isReferenceToType(type, getGlobalIteratorYieldResultType(/*reportErrors*/ false))) {
                var yieldType_1 = getTypeArguments(type)[0];
                return setCachedIterationTypes(type, "iterationTypesOfIteratorResult", createIterationTypes(yieldType_1, /*returnType*/ undefined, /*nextType*/ undefined));
            }
            if (isReferenceToType(type, getGlobalIteratorReturnResultType(/*reportErrors*/ false))) {
                var returnType_1 = getTypeArguments(type)[0];
                return setCachedIterationTypes(type, "iterationTypesOfIteratorResult", createIterationTypes(/*yieldType*/ undefined, returnType_1, /*nextType*/ undefined));
            }
            // Choose any constituents that can produce the requested iteration type.
            var yieldIteratorResult = filterType(type, isYieldIteratorResult);
            var yieldType = yieldIteratorResult !== neverType ? getTypeOfPropertyOfType(yieldIteratorResult, "value") : undefined;
            var returnIteratorResult = filterType(type, isReturnIteratorResult);
            var returnType = returnIteratorResult !== neverType ? getTypeOfPropertyOfType(returnIteratorResult, "value") : undefined;
            if (!yieldType && !returnType) {
                return setCachedIterationTypes(type, "iterationTypesOfIteratorResult", noIterationTypes);
            }
            // From https://tc39.github.io/ecma262/#sec-iteratorresult-interface
            // > ... If the iterator does not have a return value, `value` is `undefined`. In that case, the
            // > `value` property may be absent from the conforming object if it does not inherit an explicit
            // > `value` property.
            return setCachedIterationTypes(type, "iterationTypesOfIteratorResult", createIterationTypes(yieldType, returnType || voidType, /*nextType*/ undefined));
        }
        /**
         * Gets the *yield*, *return*, and *next* types of a the `next()`, `return()`, or
         * `throw()` method of an `Iterator`-like or `AsyncIterator`-like type.