Function narrowUnionMemberByTypeof

test/fixtures/snapshot/typescript.js:71120–71136

(candidate)

            // the filtered type `{}`. For this reason we narrow constituents of the union individually, in addition to
            // filtering by type-facts.
            function narrowUnionMemberByTypeof(candidate) {
                return function (type) {
                    if (isTypeSubtypeOf(type, candidate)) {
                        return type;
                    }
                    if (isTypeSubtypeOf(candidate, type)) {
                        return candidate;
                    }
                    if (type.flags & 465829888 /* TypeFlags.Instantiable */) {
                        var constraint = getBaseConstraintOfType(type) || anyType;
                        if (isTypeSubtypeOf(candidate, constraint)) {
                            return getIntersectionType([type, candidate]);
                        }
                    }
                    return type;
                };
            }
            function narrowBySwitchOnTypeOf(type, switchStatement, clauseStart, clauseEnd) {
                var switchWitnesses = getSwitchClauseTypeOfWitnesses(switchStatement, /*retainDefault*/ true);
                if (!switchWitnesses.length) {