ECMA-262 (12th Edition) ECMAScript 2021 Language Specification - page 35

.prototype.constructor

is the

intrinsic object.

The interpretation and use of the arguments of

.prototype.copyWithin

are the same as for

Array.prototype.copyWithin

as defined in

23.1.3.3

The following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. Let

relativeTarget

be ?

(

target

5. If

relativeTarget

is -

∞

, let

be 0.

6. Else if

relativeTarget

< 0, let

(

len

relativeTarget

, 0).

7. Else, let

(

relativeTarget

len

8. Let

relativeStart

start

9. If

relativeStart

is -

∞

, let

from

be 0.

10. Else if

relativeStart

< 0, let

from

len

relativeStart

, 0).

11. Else, let

from

(

relativeStart

len

12. If

end

undefined

, let

relativeEnd

len

; else let

relativeEnd

(

end

13. If

relativeEnd

is -

∞

, let

final

be 0.

14. Else if

relativeEnd

< 0, let

final

len

relativeEnd

, 0).

15. Else, let

final

(

relativeEnd

len

16. Let

count

(

final

from

len

17. If

count

> 0, then

a. NOTE: The copying must be performed in a manner that preserves the bit-level encoding of the source

data.

b. Let

buffer

.[[ViewedArrayBuffer]].

c. If

(

buffer

) is

true

, throw a

TypeError

exception.

d. Let

typedArrayName

be the String value of

.[[TypedArrayName]].

e. Let

elementSize

typedArrayName

f. Let

byteOffset

.[[ByteOffset]].

g. Let

toByteIndex

elementSize

byteOffset

h. Let

fromByteIndex

from

elementSize

byteOffset

i. Let

countBytes

count

elementSize

j. If

fromByteIndex

toByteIndex

and

toByteIndex

fromByteIndex

countBytes

, then

i. Let

direction

be -1.

ii. Set

fromByteIndex

countBytes

- 1.

iii. Set

toByteIndex

countBytes

- 1.

k. Else,

i. Let

direction

be 1.

l. Repeat, while

countBytes

> 0,

23.2.3.4 %TypedArray%.prototype.constructor

23.2.3.5 %TypedArray%.prototype.copyWithin (

target

start

[ ,

end

] )

669

i. Let

value

buffer

fromByteIndex

Uint8

true

Unordered

ii. Perform

(

buffer

toByteIndex

Uint8

value

true

Unordered

iii. Set

fromByteIndex

direction

iv. Set

toByteIndex

direction

v. Set

countBytes

- 1.

18. Return

The following steps are taken:

1. Let

be the

this

value.

(

3. Return

CreateArrayIterator

key+value

The interpretation and use of the arguments of

.prototype.every

are the same as for

Array.prototype.every

as defined in

23.1.3.5

When the

every

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

callbackfn

) is

false

, throw a

TypeError

exception.

5. Let

be 0.

6. Repeat, while

len

a. Let

be !

)).

b. Let

kValue

c. Let

testResult

(

callbackfn

thisArg

, «

kValue

»)).

d. If

testResult

false

, return

false

e. Set

+ 1.

7. Return

true

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.fill

are the same as for

Array.prototype.fill

23.1.3.6

The following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

.[[ContentType]] is

BigInt

, set

value

to ?

ToBigInt

value

5. Otherwise, set

value

to ?

ToNumber

value

6. Let

relativeStart

start

23.2.3.6 %TypedArray%.prototype.entries ( )

23.2.3.7 %TypedArray%.prototype.every (

callbackfn

[ ,

thisArg

] )

23.2.3.8 %TypedArray%.prototype.fill (

value

[ ,

start

[ ,

end

] ] )

670

7. If

relativeStart

is -

∞

, let

be 0.

8. Else if

relativeStart

< 0, let

len

relativeStart

, 0).

9. Else, let

(

relativeStart

len

10. If

end

undefined

, let

relativeEnd

len

; else let

relativeEnd

(

end

11. If

relativeEnd

is -

∞

, let

final

be 0.

12. Else if

relativeEnd

< 0, let

final

len

relativeEnd

, 0).

13. Else, let

final

(

relativeEnd

len

14. If

(

.[[ViewedArrayBuffer]]) is

true

, throw a

TypeError

exception.

15. Repeat, while

final

a. Let

be !

)).

b. Perform !

value

true

c. Set

+ 1.

16. Return

The interpretation and use of the arguments of

.prototype.filter

are the same as for

Array.prototype.filter

as defined in

23.1.3.7

When the

filter

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

callbackfn

) is

false

, throw a

TypeError

exception.

5. Let

kept

be a new empty

List

6. Let

be 0.

7. Let

captured

be 0.

8. Repeat, while

len

a. Let

be !

(

)).

b. Let

kValue

c. Let

selected

(

callbackfn

thisArg

, «

kValue

(

»)).

d. If

selected

true

, then

i. Append

kValue

to the end of

kept

ii. Set

captured

+ 1.

e. Set

+ 1.

9. Let

(

captured

) »).

10. Let

be 0.

11. For each element

kept

, do

a. Perform !

(

)),

true

b. Set

+ 1.

12. Return

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.find

are the same as for

Array.prototype.find

23.1.3.8

23.2.3.9 %TypedArray%.prototype.filter (

callbackfn

[ ,

thisArg

] )

23.2.3.10 %TypedArray%.prototype.find (

predicate

[ ,

thisArg

] )

671

When the

find

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

predicate

) is

false

, throw a

TypeError

exception.

5. Let

be 0.

6. Repeat, while

len

a. Let

be !

)).

b. Let

kValue

c. Let

testResult

(

predicate

thisArg

, «

kValue

»)).

d. If

testResult

true

, return

kValue

e. Set

+ 1.

7. Return

undefined

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.findIndex

are the same as for

Array.prototype.findIndex

23.1.3.9

When the

findIndex

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

predicate

) is

false

, throw a

TypeError

exception.

5. Let

be 0.

6. Repeat, while

len

a. Let

be !

)).

b. Let

kValue

c. Let

testResult

(

predicate

thisArg

, «

kValue

»)).

d. If

testResult

true

, return

(

e. Set

+ 1.

7. Return

-1

𝔽

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.forEach

are the same as for

Array.prototype.forEach

23.1.3.12

When the

forEach

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

callbackfn

) is

false

, throw a

TypeError

exception.

23.2.3.11 %TypedArray%.prototype.findIndex (

predicate

[ ,

thisArg

] )

23.2.3.12 %TypedArray%.prototype.forEach (

callbackfn

[ ,

thisArg

] )

672

5. Let

be 0.

6. Repeat, while

len

a. Let

be !

)).

b. Let

kValue

c. Perform ?

(

callbackfn

thisArg

, «

kValue

»).

d. Set

+ 1.

7. Return

undefined

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.includes

are the same as for

Array.prototype.includes

as defined in

23.1.3.13

When the

includes

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

len

is 0, return

false

5. Let

fromIndex

: If

fromIndex

undefined

, then

is 0.

7. If

is +

∞

, return

false

8. Else if

is -

∞

, set

to 0.

9. If

≥

0, then

a. Let

10. Else,

a. Let

len

b. If

< 0, set

to 0.

11. Repeat, while

len

a. Let

elementK

, !

))).

b. If

SameValueZero

searchElement

elementK

) is

true

, return

true

c. Set

+ 1.

12. Return

false

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.indexOf

are the same as for

Array.prototype.indexOf

23.1.3.14

When the

indexOf

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

len

is 0, return

-1

𝔽

23.2.3.13 %TypedArray%.prototype.includes (

searchElement

[ ,

fromIndex

] )

23.2.3.14 %TypedArray%.prototype.indexOf (

searchElement

[ ,

fromIndex

] )

673

5. Let

fromIndex

: If

fromIndex

undefined

, then

is 0.

7. If

is +

∞

, return

-1

𝔽

8. Else if

is -

∞

, set

to 0.

9. If

≥

0, then

a. Let

10. Else,

a. Let

len

b. If

< 0, set

to 0.

11. Repeat, while

len

a. Let

kPresent

HasProperty

(

, !

Strict Equality Comparison

))).

b. If

kPresent

true

, then

i. Let

elementK

, !

))).

ii. Let

same

be the result of performing

searchElement

===

elementK

iii. If

same

true

, return

(

c. Set

+ 1.

12. Return

-1

𝔽

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.join

are the same as for

Array.prototype.join

23.1.3.15

When the

join

method is called with one argument

separator

, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

separator

undefined

, let

sep

be the single-element String

","

5. Else, let

sep

be ?

(

separator

6. Let

be the empty String.

7. Let

be 0.

8. Repeat, while

len

a. If

> 0, set

to the

string-concatenation

and

sep

b. Let

element

be !

(

))).

c. If

element

undefined

, let

next

be the empty String; otherwise, let

next

(

element

d. Set

to the

string-concatenation

and

next

e. Set

+ 1.

9. Return

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The following steps are taken:

1. Let

be the

this

value.

23.2.3.15 %TypedArray%.prototype.join (

separator

)

23.2.3.16 %TypedArray%.prototype.keys ( )

674

(

3. Return

CreateArrayIterator

key

The interpretation and use of the arguments of

.prototype.lastIndexOf

are the same as for

Array.prototype.lastIndexOf

23.1.3.17

When the

lastIndexOf

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

len

is 0, return

-1

𝔽

5. If

fromIndex

is present, let

fromIndex

); else let

len

- 1.

6. If

is -

∞

, return

-1

𝔽

7. If

≥

0, then

a. Let

(

len

- 1).

8. Else,

a. Let

len

9. Repeat, while

≥

a. Let

kPresent

HasProperty

(

, !

Strict Equality Comparison

))).

b. If

kPresent

true

, then

i. Let

elementK

, !

))).

ii. Let

same

be the result of performing

searchElement

===

elementK

iii. If

same

true

, return

(

c. Set

- 1.

10. Return

-1

𝔽

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

.prototype.length

is an

accessor property

whose set accessor function is

undefined

. Its get

accessor function performs the following steps:

1. Let

be the

this

value.

(

, [[TypedArrayName]]).

has [[ViewedArrayBuffer]] and [[ArrayLength]] internal slots.

4. Let

buffer

.[[ViewedArrayBuffer]].

5. If

(

buffer

) is

true

, return

𝔽

6. Let

length

.[[ArrayLength]].

7. Return

length

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.map

are the same as for

23.2.3.17 %TypedArray%.prototype.lastIndexOf (

searchElement

[ ,

fromIndex

] )

23.2.3.18 get %TypedArray%.prototype.length

23.2.3.19 %TypedArray%.prototype.map (

callbackfn

[ ,

thisArg

] )

675

Array.prototype.map

as defined in

23.1.3.18

When the

map

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

callbackfn

) is

false

, throw a

TypeError

exception.

5. Let

be ?

(

len

) »).

6. Let

be 0.

7. Repeat, while

len

a. Let

be !

)).

b. Let

kValue

c. Let

mappedValue

(

callbackfn

thisArg

, «

kValue

»).

d. Perform ?

(

mappedValue

true

e. Set

+ 1.

8. Return

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.reduce

are the same as for

Array.prototype.reduce

as defined in

23.1.3.21

When the

reduce

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

callbackfn

) is

false

, throw a

TypeError

exception.

5. If

len

= 0 and

initialValue

is not present, throw a

TypeError

exception.

6. Let

be 0.

7. Let

accumulator

undefined

8. If

initialValue

is present, then

a. Set

accumulator

initialValue

9. Else,

a. Let

be !

)).

b. Set

accumulator

to !

(

c. Set

+ 1.

10. Repeat, while

len

a. Let

be !

)).

b. Let

kValue

c. Set

accumulator

to ?

(

callbackfn

undefined

, «

accumulator

kValue

»).

d. Set

+ 1.

11. Return

accumulator

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

23.2.3.20 %TypedArray%.prototype.reduce (

callbackfn

[ ,

initialValue

] )

676

The interpretation and use of the arguments of

.prototype.reduceRight

are the same as for

Array.prototype.reduceRight

23.1.3.22

When the

reduceRight

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

callbackfn

) is

false

, throw a

TypeError

exception.

5. If

len

is 0 and

initialValue

is not present, throw a

TypeError

exception.

6. Let

len

- 1.

7. Let

accumulator

undefined

8. If

initialValue

is present, then

a. Set

accumulator

initialValue

9. Else,

a. Let

be !

)).

b. Set

accumulator

to !

(

c. Set

- 1.

10. Repeat, while

≥

a. Let

be !

)).

b. Let

kValue

c. Set

accumulator

to ?

(

callbackfn

undefined

, «

accumulator

kValue

»).

d. Set

- 1.

11. Return

accumulator

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.reverse

are the same as for

Array.prototype.reverse

23.1.3.23

When the

reverse

method is called, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. Let

middle

floor

(

len

/ 2).

5. Let

lower

be 0.

6. Repeat, while

lower

≠

middle

a. Let

upper

len

lower

- 1.

b. Let

upperP

(

upper

)).

c. Let

lowerP

lower

)).

d. Let

lowerValue

be !

(

lowerP

e. Let

upperValue

be !

(

upperP

f. Perform !

lowerP

upperValue

true

g. Perform !

upperP

lowerValue

true

h. Set

lower

+ 1.

23.2.3.21 %TypedArray%.prototype.reduceRight (

callbackfn

[ ,

initialValue

] )

23.2.3.22 %TypedArray%.prototype.reverse ( )

677

7. Return

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

.prototype.set

is a function whose behaviour differs based upon the type of its first argument.

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

Sets multiple values in this

TypedArray

, reading the values from

source

. The optional

offset

value indicates the first

element index in this

TypedArray

where values are written. If omitted, it is assumed to be 0.

1. Let

target

be the

this

value.

(

target

, [[TypedArrayName]]).

target

has a [[ViewedArrayBuffer]] internal slot.

4. Let

targetOffset

be ?

SetTypedArrayFromTypedArray

(

offset

5. If

targetOffset

< 0, throw a

RangeError

exception.

6. If

source

is an Object that has a [[TypedArrayName]] internal slot, then

a. Perform ?

(

target

targetOffset

source

7. Else,

a. Perform ?

SetTypedArrayFromArrayLike

(

target

targetOffset

source

8. Return

undefined

The abstract operation SetTypedArrayFromTypedArray takes arguments

target

(a TypedArray object),

targetOffset

non-negative

integer

or +

∞

), and

source

(a TypedArray object). It sets multiple values in

target

, starting at index

targetOffset

, reading the values from

source

. It performs the following steps when called:

source

is an Object that has a [[TypedArrayName]] internal slot.

2. Let

targetBuffer

target

.[[ViewedArrayBuffer]].

3. If

(

targetBuffer

) is

true

, throw a

TypeError

exception.

4. Let

targetLength

target

.[[ArrayLength]].

5. Let

srcBuffer

source

.[[ViewedArrayBuffer]].

6. If

(

srcBuffer

) is

true

, throw a

TypeError

exception.

7. Let

targetName

be the String value of

target

.[[TypedArrayName]].

8. Let

targetType

be the Element Type value in

for

targetName

9. Let

targetElementSize

be the Element Size value specified in

targetName

10. Let

targetByteOffset

target

.[[ByteOffset]].

11. Let

srcName

be the String value of

source

.[[TypedArrayName]].

12. Let

srcType

be the Element Type value in

for

srcName

13. Let

srcElementSize

for

srcName

14. Let

srcLength

source

.[[ArrayLength]].

15. Let

srcByteOffset

source

.[[ByteOffset]].

16. If

targetOffset

is +

∞

, throw a

RangeError

exception.

17. If

srcLength

targetOffset

targetLength

, throw a

RangeError

exception.

18. If

target

.[[ContentType]]

≠

source

.[[ContentType]], throw a

TypeError

exception.

19. If both

IsSharedArrayBuffer

(

srcBuffer

) and

IsSharedArrayBuffer

(

targetBuffer

) are

true

, then

a. If

srcBuffer

.[[ArrayBufferData]] and

targetBuffer

.[[ArrayBufferData]] are the same

Shared Data Block

23.2.3.23 %TypedArray%.prototype.set (

source

[ ,

offset

] )

23.2.3.23.1 SetTypedArrayFromTypedArray (

target

targetOffset

source

)

678

values, let

same

true

; else let

same

false

20. Else, let

same

SameValue

(

srcBuffer

targetBuffer

21. If

same

true

, then

a. Let

srcByteLength

source

.[[ByteLength]].

b. Set

srcBuffer

to ?

CloneArrayBuffer

(

srcBuffer

srcByteOffset

srcByteLength

%ArrayBuffer%

c. NOTE:

%ArrayBuffer%

is used to clone

srcBuffer

because is it known to not have any observable side-

effects.

d. Let

srcByteIndex

be 0.

22. Else, let

srcByteIndex

srcByteOffset

23. Let

targetByteIndex

targetOffset

targetElementSize

targetByteOffset

24. Let

limit

targetByteIndex

targetElementSize

srcLength

25. If

srcType

is the same as

targetType

, then

a. NOTE: If

srcType

and

targetType

are the same, the transfer must be performed in a manner that preserves

the bit-level encoding of the source data.

b. Repeat, while

targetByteIndex

limit

i. Let

value

srcBuffer

srcByteIndex

Uint8

true

Unordered

ii. Perform

(

targetBuffer

targetByteIndex

Uint8

value

true

Unordered

iii. Set

srcByteIndex

+ 1.

iv. Set

targetByteIndex

+ 1.

26. Else,

a. Repeat, while

targetByteIndex

limit

i. Let

value

srcBuffer

srcByteIndex

srcType

true

Unordered

ii. Perform

(

targetBuffer

targetByteIndex

targetType

value

true

Unordered

iii. Set

srcByteIndex

srcElementSize

iv. Set

targetByteIndex

targetElementSize

The abstract operation SetTypedArrayFromArrayLike takes arguments

target

(a TypedArray object),

targetOffset

non-negative

integer

or +

∞

), and

source

(an ECMAScript value other than a TypedArray object). It sets multiple values

target

, starting at index

targetOffset

, reading the values from

source

. It performs the following steps when called:

ECMAScript language value

source

is any

other than an Object with a [[TypedArrayName]] internal

slot.

2. Let

targetBuffer

target

.[[ViewedArrayBuffer]].

3. If

(

targetBuffer

) is

true

, throw a

TypeError

exception.

4. Let

targetLength

target

.[[ArrayLength]].

5. Let

targetName

be the String value of

target

.[[TypedArrayName]].

6. Let

targetElementSize

be the Element Size value specified in

targetName

7. Let

targetType

be the Element Type value in

for

targetName

8. Let

targetByteOffset

target

.[[ByteOffset]].

9. Let

src

be ?

ToObject

source

10. Let

srcLength

LengthOfArrayLike

src

11. If

targetOffset

is +

∞

, throw a

RangeError

exception.

12. If

srcLength

targetOffset

targetLength

, throw a

RangeError

exception.

13. Let

targetByteIndex

targetOffset

targetElementSize

targetByteOffset

14. Let

be 0.

15. Let

limit

targetByteIndex

targetElementSize

srcLength

23.2.3.23.2 SetTypedArrayFromArrayLike (

target

targetOffset

source

)

679

16. Repeat, while

targetByteIndex

limit

a. Let

be !

)).

b. Let

value

be ?

src

c. If

target

.[[ContentType]] is

BigInt

, set

value

to ?

ToBigInt

value

d. Otherwise, set

value

to ?

ToNumber

value

e. If

(

targetBuffer

) is

true

, throw a

TypeError

exception.

f. Perform

(

targetBuffer

targetByteIndex

targetType

value

true

Unordered

g. Set

+ 1.

h. Set

targetByteIndex

targetElementSize

The interpretation and use of the arguments of

.prototype.slice

are the same as for

Array.prototype.slice

as defined in

23.1.3.25

. The following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. Let

relativeStart

start

5. If

relativeStart

is -

∞

, let

be 0.

6. Else if

relativeStart

< 0, let

len

relativeStart

, 0).

7. Else, let

(

relativeStart

len

8. If

end

undefined

, let

relativeEnd

len

; else let

relativeEnd

(

end

9. If

relativeEnd

is -

∞

, let

final

be 0.

10. Else if

relativeEnd

< 0, let

final

len

relativeEnd

, 0).

11. Else, let

final

(

relativeEnd

len

12. Let

count

(

final

, 0).

13. Let

(

count

) »).

14. If

count

> 0, then

a. If

(

.[[ViewedArrayBuffer]]) is

true

, throw a

TypeError

exception.

b. Let

srcName

be the String value of

.[[TypedArrayName]].

c. Let

srcType

be the Element Type value in

for

srcName

d. Let

targetName

be the String value of

.[[TypedArrayName]].

e. Let

targetType

be the Element Type value in

for

targetName

f. If

srcType

is different from

targetType

, then

i. Let

be 0.

ii. Repeat, while

final

1. Let

be !

)).

2. Let

kValue

3. Perform !

(

)),

kValue

true

4. Set

+ 1.

5. Set

+ 1.

g. Else,

i. Let

srcBuffer

.[[ViewedArrayBuffer]].

ii. Let

targetBuffer

.[[ViewedArrayBuffer]].

iii. Let

elementSize

for Element Type

srcType

iv. NOTE: If

srcType

and

targetType

are the same, the transfer must be performed in a manner that

preserves the bit-level encoding of the source data.

23.2.3.24 %TypedArray%.prototype.slice (

start

end

)

680

v. Let

srcByteOffset

.[[ByteOffset]].

vi. Let

targetByteIndex

.[[ByteOffset]].

vii. Let

srcByteIndex

be (

elementSize

) +

srcByteOffset

viii. Let

limit

targetByteIndex

count

elementSize

ix. Repeat, while

targetByteIndex

limit

1. Let

value

srcBuffer

srcByteIndex

Uint8

true

Unordered

2. Perform

(

targetBuffer

targetByteIndex

Uint8

value

true

Unordered

3. Set

srcByteIndex

+ 1.

4. Set

targetByteIndex

+ 1.

15. Return

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

The interpretation and use of the arguments of

.prototype.some

are the same as for

Array.prototype.some

23.1.3.26

When the

some

method is called with one or two arguments, the following steps are taken:

1. Let

be the

this

value.

(

3. Let

len

.[[ArrayLength]].

4. If

callbackfn

) is

false

, throw a

TypeError

exception.

5. Let

be 0.

6. Repeat, while

len

a. Let

be !

)).

b. Let

kValue

c. Let

testResult

(

callbackfn

thisArg

, «

kValue

»)).

d. If

testResult

true

, return

true

e. Set

+ 1.

7. Return

false

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

.prototype.sort

is a distinct function that, except as described below, implements the same

requirements as those of

Array.prototype.sort

. The implementation of the

23.1.3.27

object that has a fixed length and whose

.prototype.sort

specification may be optimized with the knowledge that the

this

value is an

integer-indexed

properties are not sparse.

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

Upon entry, the following steps are performed to initialize evaluation of the

sort

function. These steps are used

instead of steps

–

23.1.3.27

1. If

comparefn

is not

undefined

and

(

comparefn

) is

false

, throw a

TypeError

exception.

2. Let

obj

be the

this

value.

3. Let

buffer

(

obj

23.2.3.25 %TypedArray%.prototype.some (

callbackfn

[ ,

thisArg

] )

23.2.3.26 %TypedArray%.prototype.sort (

comparefn

)

681

4. Let

len

obj

.[[ArrayLength]].

The following version of

SortCompare

is used by

comparison rather than the string comparison used in

.prototype.sort

. It performs a numeric

23.1.3.27

The abstract operation TypedArraySortCompare takes arguments

and

. It also has access to the

comparefn

and

buffer

values of the current invocation of the

sort

method. It performs the following steps when called:

: Both

) are Number or both are BigInt.

2. If

comparefn

is not

undefined

, then

a. Let

be ?

ToNumber

comparefn

undefined

, «

»)).

b. If

(

buffer

) is

true

, throw a

TypeError

exception.

c. If

NaN

, return

𝔽

d. Return

3. If

and

are both

NaN

, return

𝔽

4. If

NaN

, return

𝔽

5. If

NaN

, return

-1

𝔽

6. If

, return

-1

𝔽

7. If

, return

𝔽

8. If

-0

𝔽

and

𝔽

, return

-1

𝔽

9. If

𝔽

and

-0

𝔽

, return

𝔽

10. Return

𝔽

NOTE

Returns a new

TypedArray

object whose element type is the same as this

TypedArray

and whose ArrayBuffer is the

same as the ArrayBuffer of this

TypedArray

, referencing the elements at

begin

, inclusive, up to

end

, exclusive. If either

begin

end

is negative, it refers to an index from the end of the array, as opposed to from the beginning.

1. Let

be the

this

value.

(

, [[TypedArrayName]]).

has a [[ViewedArrayBuffer]] internal slot.

4. Let

buffer

.[[ViewedArrayBuffer]].

5. Let

srcLength

.[[ArrayLength]].

6. Let

relativeBegin

be ?

(

begin

7. If

relativeBegin

is -

∞

, let

beginIndex

be 0.

8. Else if

relativeBegin

< 0, let

beginIndex

srcLength

relativeBegin

, 0).

9. Else, let

beginIndex

relativeBegin

srcLength

10. If

end

undefined

, let

relativeEnd

srcLength

; else let

relativeEnd

end

11. If

relativeEnd

is -

∞

, let

endIndex

be 0.

12. Else if

relativeEnd

< 0, let

endIndex

srcLength

relativeEnd

, 0).

13. Else, let

endIndex

(

relativeEnd

srcLength

14. Let

newLength

endIndex

beginIndex

, 0).

15. Let

constructorName

be the String value of

.[[TypedArrayName]].

Because

NaN

always compares greater than any other value,

NaN

property values always sort to

the end of the result when

comparefn

is not provided.

23.2.3.27 %TypedArray%.prototype.subarray (

begin

end

)

682

16. Let

elementSize

constructorName

17. Let

srcByteOffset

.[[ByteOffset]].

18. Let

beginByteOffset

srcByteOffset

beginIndex

elementSize

19. Let

argumentsList

be «

buffer

(

beginByteOffset

(

newLength

) ».

20. Return ?

argumentsList

This function is not generic. The

this

value must be an object with a [[TypedArrayName]] internal slot.

.prototype.toLocaleString

is a distinct function that implements the same algorithm as

Array.prototype.toLocaleString

This function is not generic.

23.1.3.29

except that the

this

value's [[ArrayLength]]

internal slot is accessed in place of performing a [[Get]] of

"length"

. The implementation of the algorithm may be

optimized with the knowledge that the

this

value is an object that has a fixed length and whose

integer-indexed

properties are not sparse. However, such optimization must not introduce any observable changes in the specified
behaviour of the algorithm.

is applied to the

this

value prior to evaluating the algorithm. If its

result is an

abrupt completion

that exception is thrown instead of evaluating the algorithm.

NOTE

The initial value of the

.prototype.toString

as the

Array.prototype.toString

method defined in

23.1.3.30

The following steps are taken:

1. Let

be the

this

value.

(

3. Return

CreateArrayIterator

as the initial value of the

value

The initial value of the

@@iterator

property is the same

function object

.prototype.values

property.

whose set accessor function is

.prototype[@@toStringTag]

is an

accessor property

undefined

. Its get accessor function performs the following steps:

1. Let

be the

this

value.

If the ECMAScript implementation includes the ECMA-402 Internationalization API this function
is based upon the algorithm for

Array.prototype.toLocaleString

that is in the

ECMA-402 specification.

23.2.3.28 %TypedArray%.prototype.toLocaleString ( [

reserved1

[ ,

reserved2

] ] )

23.2.3.29 %TypedArray%.prototype.toString ( )

23.2.3.30 %TypedArray%.prototype.values ( )

23.2.3.31 %TypedArray%.prototype [ @@iterator ] ( )

23.2.3.32 get %TypedArray%.prototype [ @@toStringTag ]

683

2. If

Type

(

) is not Object, return

undefined

3. If

does not have a [[TypedArrayName]] internal slot, return

undefined

4. Let

name

.[[TypedArrayName]].

Type

name

) is String.

6. Return

name

This property has the attributes { [[Enumerable]]:

false

, [[Configurable]]:

true

The initial value of the

"name"

property of this function is

"get [Symbol.toStringTag]"

The abstract operation TypedArraySpeciesCreate takes arguments

exemplar

and

argumentList

. It is used to specify the

creation of a new TypedArray object using a

constructor

function that is derived from

exemplar

. It performs the

following steps when called:

exemplar

is an Object that has [[TypedArrayName]] and [[ContentType]] internal slots.

2. Let

defaultConstructor

be the intrinsic object listed in column one of

exemplar

.[[TypedArrayName]].

3. Let

constructor

SpeciesConstructor

(

exemplar

defaultConstructor

4. Let

result

be ?

TypedArrayCreate

constructor

argumentList

result

has [[TypedArrayName]] and [[ContentType]] internal slots.

6. If

result

.[[ContentType]]

≠

exemplar

.[[ContentType]], throw a

TypeError

exception.

7. Return

result

The abstract operation TypedArrayCreate takes arguments

constructor

and

argumentList

. It is used to specify the

creation of a new TypedArray object using a

constructor

function. It performs the following steps when called:

1. Let

newTypedArray

Construct

(

constructor

argumentList

(

newTypedArray

3. If

argumentList

is a

List

of a single Number, then

a. If

newTypedArray

.[[ArrayLength]] <

(

argumentList

[0]), throw a

TypeError

exception.

4. Return

newTypedArray

The abstract operation ValidateTypedArray takes argument

. It performs the following steps when called:

1. Perform ?

(

, [[TypedArrayName]]).

has a [[ViewedArrayBuffer]] internal slot.

3. Let

buffer

.[[ViewedArrayBuffer]].

4. If