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Correct falsiness for {} empty object type

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This commit is contained in:
Anders Hejlsberg 2018-09-17 09:06:26 -07:00
parent 394ee31a56
commit acb8b1f65f
1 changed files with 30 additions and 21 deletions
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51
src/compiler/checker.ts
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@ -601,6 +601,8 @@ namespace ts {
FunctionFacts = FunctionStrictFacts | EQUndefined | EQNull | EQUndefinedOrNull | Falsy,
UndefinedFacts = TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEObject | TypeofNEFunction | TypeofNEHostObject | EQUndefined | EQUndefinedOrNull | NENull | Falsy,
NullFacts = TypeofEQObject | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | TypeofNEHostObject | EQNull | EQUndefinedOrNull | NEUndefined | Falsy,
EmptyObjectStrictFacts = All & ~(EQUndefined | EQNull | EQUndefinedOrNull),
EmptyObjectFacts = All,
}
const typeofEQFacts = createMapFromTemplate({
@ -11774,8 +11776,12 @@ namespace ts {
const simplified = getSimplifiedType((<IndexType>target).type);
const constraint = simplified !== (<IndexType>target).type ? simplified : getConstraintOfType((<IndexType>target).type);
if (constraint) {
if (result = isRelatedTo(source, getIndexType(constraint, (target as IndexType).stringsOnly), reportErrors)) {
return result;
// We require Ternary.True here such that circular constraints don't cause
// false positives. For example, given 'T extends { [K in keyof T]: string }',
// 'keyof T' has itself as its constraint and produces a Ternary.Maybe when
// related to other types.
if (isRelatedTo(source, getIndexType(constraint, (target as IndexType).stringsOnly), reportErrors) === Ternary.True) {
return Ternary.True;
}
}
}
@ -14169,9 +14175,11 @@ namespace ts {
(type === falseType || type === regularFalseType) ? TypeFacts.FalseFacts : TypeFacts.TrueFacts;
}
if (flags & TypeFlags.Object) {
return isFunctionObjectType(<ObjectType>type) ?
strictNullChecks ? TypeFacts.FunctionStrictFacts : TypeFacts.FunctionFacts :
strictNullChecks ? TypeFacts.ObjectStrictFacts : TypeFacts.ObjectFacts;
return getObjectFlags(type) & ObjectFlags.Anonymous && isEmptyObjectType(<ObjectType>type) ?
strictNullChecks ? TypeFacts.EmptyObjectStrictFacts : TypeFacts.EmptyObjectFacts :
isFunctionObjectType(<ObjectType>type) ?
strictNullChecks ? TypeFacts.FunctionStrictFacts : TypeFacts.FunctionFacts :
strictNullChecks ? TypeFacts.ObjectStrictFacts : TypeFacts.ObjectFacts;
}
if (flags & (TypeFlags.Void | TypeFlags.Undefined)) {
return TypeFacts.UndefinedFacts;
@ -15083,23 +15091,24 @@ namespace ts {
return getTypeWithFacts(assumeTrue ? mapType(type, narrowTypeForTypeof) : type, facts);
function narrowTypeForTypeof(type: Type) {
if (assumeTrue && !(type.flags & TypeFlags.Union)) {
if (type.flags & TypeFlags.Unknown && literal.text === "object") {
return getUnionType([nonPrimitiveType, nullType]);
if (type.flags & TypeFlags.Unknown && literal.text === "object") {
return getUnionType([nonPrimitiveType, nullType]);
}
// We narrow a non-union type to an exact primitive type if the non-union type
// is a supertype of that primitive type. For example, type 'any' can be narrowed
// to one of the primitive types.
const targetType = literal.text === "function" ? globalFunctionType : typeofTypesByName.get(literal.text);
if (targetType) {
if (isTypeSubtypeOf(type, targetType)) {
return type;
}
// We narrow a non-union type to an exact primitive type if the non-union type
// is a supertype of that primitive type. For example, type 'any' can be narrowed
// to one of the primitive types.
const targetType = literal.text === "function" ? globalFunctionType : typeofTypesByName.get(literal.text);
if (targetType) {
if (isTypeSubtypeOf(targetType, type)) {
return isTypeAny(type) ? targetType : getIntersectionType([type, targetType]); // Intersection to handle `string` being a subtype of `keyof T`
}
if (type.flags & TypeFlags.Instantiable) {
const constraint = getBaseConstraintOfType(type) || anyType;
if (isTypeSubtypeOf(targetType, constraint)) {
return getIntersectionType([type, targetType]);
}
if (isTypeSubtypeOf(targetType, type)) {
return targetType;
}
if (type.flags & TypeFlags.Instantiable) {
const constraint = getBaseConstraintOfType(type) || anyType;
if (isTypeSubtypeOf(targetType, constraint)) {
return getIntersectionType([type, targetType]);
}
}
}