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type narrowing by constructor signiture of interface

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vvakame
2015-04-30 23:12:35 +09:00
parent 64f3798bd7
commit 35d6e98e98
4 changed files with 368 additions and 9 deletions
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src/compiler/checker.ts
+31 -9
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@@ -5351,17 +5351,39 @@ module ts {
}
// Target type is type of prototype property
let prototypeProperty = getPropertyOfType(rightType, "prototype");
if (!prototypeProperty) {
return type;
if (prototypeProperty) {
let targetType = getTypeOfSymbol(prototypeProperty);
if (targetType !== anyType) {
// Narrow to target type if it is a subtype of current type
if (isTypeSubtypeOf(targetType, type)) {
return targetType;
}
// If current type is a union type, remove all constituents that aren't subtypes of target type
if (type.flags & TypeFlags.Union) {
return getUnionType(filter((<UnionType>type).types, t => isTypeSubtypeOf(t, targetType)));
}
}
}
let targetType = getTypeOfSymbol(prototypeProperty);
// Narrow to target type if it is a subtype of current type
if (isTypeSubtypeOf(targetType, type)) {
return targetType;
// Target type is type of constructor signiture
let constructorSignitures: Signature[];
if (rightType.flags & TypeFlags.Interface) {
constructorSignitures = (<InterfaceTypeWithDeclaredMembers>rightType).declaredConstructSignatures;
}
// If current type is a union type, remove all constituents that aren't subtypes of target type
if (type.flags & TypeFlags.Union) {
return getUnionType(filter((<UnionType>type).types, t => isTypeSubtypeOf(t, targetType)));
if (rightType.flags & TypeFlags.Anonymous) {
constructorSignitures = (<ResolvedType>rightType).constructSignatures;
}
if (constructorSignitures) {
let constructorType = getUnionType(map(constructorSignitures, constructorSignature => {
if (constructorSignature.typeParameters && constructorSignature.typeParameters.length !== 0) {
// TODO convert type parameters to any or empty object types. e.g. Sample<T> -> Sample<any> or Sample<{}>.
}
return constructorSignature.resolvedReturnType;
}));
// Pickup type from union types
if (type.flags & TypeFlags.Union) {
return getUnionType(filter((<UnionType>type).types, t => isTypeSubtypeOf(t, constructorType)));
}
return constructorType;
}
return type;
}