Stage 1 Draft / September 20, 2023

Get Intrinsic

6 ECMAScript Data Types and Values

6.1 ECMAScript Language Types

6.1.7 The Object Type

6.1.7.4 Well-Known Intrinsic Objects

Well-known intrinsics are built-in objects that are explicitly referenced by the algorithms of this specification and which usually have realm-specific identities. Unless otherwise specified each intrinsic object actually corresponds to a set of similar objects, one per realm.

Within this specification a reference such as %name% means the intrinsic object, associated with the current realm, corresponding to the name. A reference such as %name.a.b% means, as if the "b" property of the value of the "a" property of the intrinsic object %name% was accessed prior to any ECMAScript code being evaluated. Determination of the current realm and its intrinsics is described in 9.4. The well-known intrinsics are listed in Table 1.

Table 1: Well-Known Intrinsic Objects
Intrinsic Name Global Name ECMAScript Language Association Directly Accessible to ECMAScript code
%AggregateError% AggregateError The AggregateError constructor (20.5.7.1)
%AsyncFromSyncIteratorPrototype% The prototype of async-from-sync iterator objects (27.1.4) No
%ForInIteratorPrototype% The prototype of For-In iterator objects (14.7.5.10) No

7 Abstract Operations

7.5 Miscellaneous

7.5.1 HostAddedIntrinsics ( )

The host-defined abstract operation HostAddedIntrinsics takes no arguments and returns a List of Records. It allows host environments to provide additional intrinsics for getIntrinsics to expose.

An implementation of HostAddedIntrinsics must conform to the following requirements:

  • Every item in the returned list must be a Record with fields [[Key]] (the intrinsic name) and [[Value]] (the intrinsic value itself).
  • An intrinsic name that describes a data property must have no prefix.
  • An intrinsic name that describes an accessor property must have the prefix "get " or "set ".
  • Every call to this abstract operation must return the same List contents, in the same order.

The default implementation of HostAddedIntrinsics is to return an empty List.

7.5.2 GetIntrinsicsMap ( )

The abstract operation GetIntrinsicsMap takes no arguments and returns a Map.

GetIntrinsicsMap returns a Map object. This Map is not directly observable from ECMAScript code.

Note
The returned Map object must be identical on successive calls to this abstract operation.
  1. Let intrinsics be a new empty List.
  2. Let baseIntrinsics be a list of each intrinsic name listed in 6.1.7.4.
  3. Sort baseIntrinsics alphabetically, with a case-insensitive ordering.
  4. For each baseIntrinsic of baseIntrinscs,
    1. Append Record { [[Key]]: baseIntrinsic, [[Value]]: the referenced intrinsic value } to intrinsics.
    2. Let nestedIntrinsics be a new empty List.
    3. For each intrinsic intrinsic that would be accessible from the value represented by baseIntrinsic in a new realm prior to any ECMAScript code being evaluated, via member access,
      1. Let P be the property key represented by intrinsic.
      2. Let X be the property represented by intrinsic.
      3. If P is neither "constructor" nor "__proto__",
        1. If X is a data property,
          1. Let value be the [[Value]] attribute of X.
          2. Append Record { [[Key]]: intrinsic, [[Value]]: value } to nestedIntrinsics.
        2. Else,
          1. Assert: X is an accessor property.
          2. Let get be the [[Get]] attribute of X.
          3. If get is not undefined,
            1. Let name be the string-concatenation of "get " and intrinsic.
            2. Append Record { [[Key]]: name, [[Value]]: get } to nestedIntrinsics.
          4. Let set be the [[Set]] attribute of X.
          5. If set is not undefined,
            1. Let name be the string-concatenation of "set " and intrinsic.
            2. Append Record { [[Key]]: name, [[Value]]: set } to nestedIntrinsics.
    4. TODO: find an easy way to sort that ignores the prefixes.
    5. Sort nestedIntrinsics in alphabetical order, based on the [[Key]] field of each Record.
    6. Append the contents of nestedIntrinsics to intrinsics.
  5. Append Record { [[Key]]: "globalThis", [[Value]]: GetThisBinding() } to intrinsics.
  6. Assert: intrinsics contains exactly one record with the [[Key]] "globalThis".
  7. Let hostIntrinsics be HostAddedIntrinsics().
  8. Let map be ! OrdinaryCreateFromConstructor(%Map%, "%Map.prototype%", « [[MapData]] »).
  9. Set map.[[MapData]] to the list-concatenation of intrinsics and hostIntrinsics.
  10. Return map.

7.5.3 CreateIntrinsicsIterator ( )

The abstract operation CreateIntrinsicsIterator takes no arguments and returns a Generator. It performs the following steps when called:

  1. Return ! CreateMapIterator(GetIntrinsicsMap(), key).

7.5.4 MapGet ( map, key )

The abstract operation MapGet takes arguments map (a Map) and key (an ECMAScript language value) and returns a Boolean. It performs the following steps when called:

  1. Let entries be the List that is map.[[MapData]].
  2. For each Record { [[Key]], [[Value]] } p of entries, do
    1. If p.[[Key]] is not empty and SameValueZero(p.[[Key]], key) is true, return p.[[Value]].
  3. Return undefined.

7.5.5 MapHas ( map, key )

The abstract operation MapHas takes arguments map (a Map) and key (an ECMAScript language value) and returns a Boolean. It performs the following steps when called:

  1. Let entries be the List that is map.[[MapData]].
  2. For each Record { [[Key]], [[Value]] } p of entries, do
    1. If p.[[Key]] is not empty and SameValueZero(p.[[Key]], key) is true, return true.
  3. Return false.

24 Keyed Collections

24.1 Map Objects

24.1.3 Properties of the Map Prototype Object

24.1.3.6 Map.prototype.get ( key )

This method performs the following steps when called:

  1. Let M be the this value.
  2. Perform ? RequireInternalSlot(M, [[MapData]]).
  3. Return MapGet(M, key).
  4. Let entries be the List that is M.[[MapData]].
  5. For each Record { [[Key]], [[Value]] } p of entries, do
    1. If p.[[Key]] is not empty and SameValueZero(p.[[Key]], key) is true, return p.[[Value]].
  6. Return undefined.

24.1.3.7 Map.prototype.has ( key )

This method performs the following steps when called:

  1. Let M be the this value.
  2. Perform ? RequireInternalSlot(M, [[MapData]]).
  3. Return MapHas(M, key).
  4. Let entries be the List that is M.[[MapData]].
  5. For each Record { [[Key]], [[Value]] } p of entries, do
    1. If p.[[Key]] is not empty and SameValueZero(p.[[Key]], key) is true, return p.[[Value]].
  6. Return undefined.

28 Reflection

28.1 The Reflect Object

28.1.6 Reflect.getIntrinsic ( name )

This function performs the following steps when called:

  1. If Type(name) is not String, throw a TypeError exception.
  2. Let map be GetIntrinsicsMap().
  3. If MapHas(map) is false, then
    1. Throw a TypeError exception.
  4. Return MapGet(map, name).
 Note
When the name string succeeds in producing an intrinsic, the name string surrounded by "%" matches the intrinsic notation described in the specification in Well-Known Intrinsic Objects.

28.1.7 Reflect.getIntrinsics ( )

This function performs the following steps when called:

  1. Return CreateIntrinsicsIterator().

A Copyright & Software License

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© 2023 Jordan Harband

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