com.google.javascript.rhino.jstype

Class UnknownType

java.lang.Object

com.google.javascript.rhino.jstype.JSType

com.google.javascript.rhino.jstype.ObjectType

com.google.javascript.rhino.jstype.UnknownType

All Implemented Interfaces:

StaticScope<JSType>, Serializable

public class UnknownType
extends ObjectType

The Unknown type.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.google.javascript.rhino.jstype.JSType

JSType.TypePair

Field Summary

Fields inherited from class com.google.javascript.rhino.jstype.JSType

EMPTY_TYPE_COMPONENT, ENUMDECL, NOT_A_CLASS, NOT_A_TYPE, NOT_ENUMDECL, templateTypeMap, UNKNOWN_NAME

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canBeCalled() This predicate is used to test whether a given type can be used as the 'function' in a function call.
FunctionType	getConstructor() Gets this object's constructor.
String	getDisplayName() Returns a user meaningful label for the JSType instance.
ObjectType	getImplicitPrototype() Gets the implicit prototype (a.k.a.
BooleanLiteralSet	getPossibleToBooleanOutcomes() Computes the set of possible outcomes of the ToBoolean predicate for this type.
String	getReferenceName() Gets the reference name for this object.
boolean	hasDisplayName()
boolean	isCheckedUnknownType()
boolean	isNullable() Tests whether this type is nullable.
boolean	isSubtype(JSType that) Checks whether this is a subtype of that.
boolean	isUnknownType() We treat this as the unknown type if any of its implicit prototype properties is unknown.
boolean	matchesNumberContext() This predicate is used to test whether a given type can appear in a numeric context, such as an operand of a multiply operator.
boolean	matchesObjectContext() This predicate is used to test whether a given type can appear in an Object context, such as the expression in a with statement.
boolean	matchesStringContext() This predicate is used to test whether a given type can appear in a String context, such as an operand of a string concat (+) operator.
TernaryValue	testForEquality(JSType that) Compares this and that.
<T> T	visit(Visitor<T> visitor) Visit this type with the given visitor.

Methods inherited from class com.google.javascript.rhino.jstype.ObjectType

cast, clearCachedValues, createDelegateSuffix, defineDeclaredProperty, defineInferredProperty, defineSynthesizedProperty, findPropertyType, getCtorExtendedInterfaces, getCtorImplementedInterfaces, getJSDocInfo, getNormalizedReferenceName, getOwnerFunction, getOwnPropertyJSDocInfo, getOwnPropertyNames, getOwnSlot, getParentScope, getPropertiesCount, getPropertyNames, getPropertyNode, getPropertyType, getRootNode, getSlot, getTemplateTypes, getTypeOfThis, hasCachedValues, hasOwnProperty, hasProperty, hasReferenceName, isFunctionPrototypeType, isNativeObjectType, isObject, isPropertyInExterns, isPropertyTypeDeclared, isPropertyTypeInferred, removeProperty, setJSDocInfo, setPropertyJSDocInfo

Methods inherited from class com.google.javascript.rhino.jstype.JSType

autobox, autoboxesTo, canCastTo, canTestForEqualityWith, canTestForShallowEqualityWith, clearResolved, collapseUnion, dereference, differsFrom, equals, extendTemplateTypeMap, getGreatestSubtype, getLeastSupertype, getRestrictedTypeGivenToBooleanOutcome, getTemplateTypeMap, getTypesUnderEquality, getTypesUnderInequality, getTypesUnderShallowEquality, getTypesUnderShallowInequality, hasAnyTemplateTypes, hashCode, isAllType, isArrayType, isBooleanObjectType, isBooleanValueType, isConstructor, isDateType, isDict, isEmptyType, isEnumElementType, isEnumType, isEquivalent, isEquivalentTo, isFunctionType, isGlobalThisType, isInstanceType, isInterface, isInvariant, isNominalConstructor, isNominalType, isNoObjectType, isNoResolvedType, isNoType, isNullType, isNumber, isNumberObjectType, isNumberValueType, isOrdinaryFunction, isRecordType, isRegexpType, isResolved, isString, isStringObjectType, isStringValueType, isStruct, isTemplateType, isTemplatizedType, isUnionType, isVoidType, matchConstraint, matchesInt32Context, matchesUint32Context, resolve, restrictByNotNullOrUndefined, setValidator, toAnnotationString, toDebugHashCodeString, toMaybeEnumElementType, toMaybeEnumType, toMaybeFunctionType, toMaybeFunctionType, toMaybeTemplateType, toMaybeTemplateType, toMaybeTemplatizedType, toMaybeTemplatizedType, toMaybeUnionType, toObjectType, toString, unboxesTo

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

isUnknownType

public boolean isUnknownType()

Description copied from class: ObjectType

We treat this as the unknown type if any of its implicit prototype properties is unknown.

Overrides:

isUnknownType in class ObjectType

isCheckedUnknownType

public boolean isCheckedUnknownType()

Overrides:

isCheckedUnknownType in class JSType

canBeCalled

public boolean canBeCalled()

Description copied from class: JSType

This predicate is used to test whether a given type can be used as the 'function' in a function call.

Overrides:

canBeCalled in class JSType

Returns:

true if this type might be callable.

matchesNumberContext

public boolean matchesNumberContext()

Description copied from class: JSType

This predicate is used to test whether a given type can appear in a numeric context, such as an operand of a multiply operator.

Overrides:

matchesNumberContext in class JSType

matchesObjectContext

public boolean matchesObjectContext()

Description copied from class: JSType

This predicate is used to test whether a given type can appear in an Object context, such as the expression in a with statement. Most types we will encounter, except notably null, have at least the potential for converting to Object. Host defined objects can get peculiar.

Overrides:

matchesObjectContext in class JSType

matchesStringContext

public boolean matchesStringContext()

Description copied from class: JSType

This predicate is used to test whether a given type can appear in a String context, such as an operand of a string concat (+) operator. All types have at least the potential for converting to String. When we add externally defined types, such as a browser OM, we may choose to add types that do not automatically convert to String.

Overrides:

matchesStringContext in class JSType

testForEquality

public TernaryValue testForEquality(JSType that)

Description copied from class: JSType

Compares this and that.

Overrides:

testForEquality in class ObjectType

Returns:

• TernaryValue.TRUE if the comparison of values of this type and that always succeed (such as undefined compared to null)
• TernaryValue.FALSE if the comparison of values of this type and that always fails (such as undefined compared to number)
• TernaryValue.UNKNOWN if the comparison can succeed or fail depending on the concrete values

isNullable

public boolean isNullable()

Description copied from class: JSType

Tests whether this type is nullable.

Overrides:

isNullable in class JSType

isSubtype

public boolean isSubtype(JSType that)

Description copied from class: JSType

Checks whether this is a subtype of that.

Subtyping rules:

• (unknown) — every type is a subtype of the Unknown type.
• (no) — the No type is a subtype of every type.
• (no-object) — the NoObject type is a subtype of every object type (i.e. subtypes of the Object type).
• (ref) — a type is a subtype of itself.
• (union-l) — A union type is a subtype of a type U if all the union type's constituents are a subtype of U. Formally
  (T<sub>1</sub>, &hellip;, T<sub>n</sub>) &lt;: U if and only T<sub>k</sub> &lt;: U for all k ∈ 1..n.
• (union-r) — A type U is a subtype of a union type if it is a subtype of one of the union type's constituents. Formally
  U &lt;: (T<sub>1</sub>, &hellip;, T<sub>n</sub>) if and only if U &lt;: T<sub>k</sub> for some index k.
• (objects) — an Object O<sub>1</sub> is a subtype of an object O<sub>2</sub> if it has more properties than O<sub>2</sub> and all common properties are pairwise subtypes.

Overrides:

isSubtype in class JSType

Returns:

this <: that

visit

public <T> T visit(Visitor<T> visitor)

Description copied from class: JSType

Visit this type with the given visitor.

Overrides:

visit in class ObjectType

Returns:

the value returned by the visitor

See Also:

Visitor

getImplicitPrototype

public ObjectType getImplicitPrototype()

Description copied from class: ObjectType

Gets the implicit prototype (a.k.a. the [[Prototype]] property).

Specified by:

getImplicitPrototype in class ObjectType

getConstructor

public FunctionType getConstructor()

Description copied from class: ObjectType

Gets this object's constructor.

Specified by:

getConstructor in class ObjectType

Returns:

this object's constructor or null if it is a native object (constructed natively v.s. by instantiation of a function)

getReferenceName

public String getReferenceName()

Description copied from class: ObjectType

Gets the reference name for this object. This includes named types like constructors, prototypes, and enums. It notably does not include literal types like strings and booleans and structural types.

Specified by:

getReferenceName in class ObjectType

Returns:

the object's name or null if this is an anonymous object

getDisplayName

public String getDisplayName()

Description copied from class: JSType

Returns a user meaningful label for the JSType instance. For example, Functions and Enums will return their declaration name (if they have one). Some types will not have a meaningful display name. Calls to hasDisplayName() will return true IFF getDisplayName() will return null or a zero length string.

Overrides:

getDisplayName in class ObjectType

Returns:

the display name of the type, or null if one is not available

hasDisplayName

public boolean hasDisplayName()

Overrides:

hasDisplayName in class JSType

Returns:

true if the JSType has a user meaningful label.

getPossibleToBooleanOutcomes

public BooleanLiteralSet getPossibleToBooleanOutcomes()

Description copied from class: JSType

Computes the set of possible outcomes of the ToBoolean predicate for this type. The ToBoolean predicate is defined by the ECMA-262 standard, 3^rd edition. Its behavior for simple types can be summarized by the following table:

type	result
undefined	{false}
null	{false}
boolean	{true, false}
number	{true, false}
string	{true, false}
Object	{true}

Overrides:

getPossibleToBooleanOutcomes in class ObjectType

Returns:

the set of boolean literals for this type