Status and Roadmap

Current state of development is tracked in GitHub projects.

High level status

• Most of TypeScript's AOT-compatible syntax is supported
• Manual memory management is in but GC remains to do
• Classes are still wonky when it comes to the details
• Standard library is very basic and needs a lot of work
• No exception support yet, waiting for WebAssembly/exception-handling to land
• We need more tests (pretty sure this will remain here)

High level goals

• Get a memory manager and GC combo up and running
  • Memory manager
  • GC
• Get a standard library up that "just works" (where AOT-compatible)
• Improve linking, e.g. with C, based on what's supported by common tools
• Compile the AssemblyScript compiler to WebAssembly using itself
• Provide tools to automatically generate glue code and definitions

And, of course, keep up with the state of WebAssembly, most notably at this point:

Proposal	Phase	Status
Sign Extension Operations	standardize	--enable sign-extension
Mutable Globals	standardize	--enable mutable-global
Non-trapping float-to-int Conversions	standardize
Reference Types	implementation
Multi-value	implementation
Bulk Memory Operations	standardize	--enable bulk-memory
SIMD	implementation	--enable simd
Threads	implementation
Exception handling	proposal
Host Bindings	proposal
GC	proposal

Standard library compatibility

AssemblyScript comes with its own lightweight standard library that aims to be as compatible as it can get to what you'd expect in the browser. The following table outlines what's implemented already:

Feature		Notes
Globals
NaN	✓	Context-sensitive (f32 in f32 context, otherwise f64)
Infinity	✓	Context-sensitive (f32 in f32 context, otherwise f64)
isFinite	✓
isNaN	✓
parseFloat	✓	Naive implementation
parseInt	✓
decodeURI
decodeURIComponent
encodeURI
encodeURIComponent
Number		There is no Number object in AssemblyScript, but one for each type instead.
EPSILON	✓
MIN_VALUE	✓
MAX_VALUE	✓
MIN_NORMAL_VALUE	✓	AssemblyScript specific
MIN_SAFE_INTEGER	✓
MAX_SAFE_INTEGER	✓
NaN	✓
NEGATIVE_INFINITY	✓
POSITIVE_INFINITY	✓
isFinite	✓
isInteger	✓
isNaN	✓
isSafeInteger	✓
parseFloat	✓	Naive implementation
parseInt	✓
toExponential
toFixed
toLocaleString
toPrecision
toString	✓
Array
length	✓
from
isArray	✓
of
concat	✓
copyWithin	✓
entries
every	✓	No closures yet
fill	✓
filter	✓	No closures yet
find
findIndex	✓	No closures yet
flat
flatMap
forEach	✓	No closures yet
includes	✓
indexOf	✓
join	✓
keys
lastIndexOf	✓
map	✓	No closures yet
pop	✓
push	✓
reduce	✓	No closures yet
reduceRight	✓	No closures yet
reverse	✓
shift	✓
slice	✓
some	✓	No closures yet
sort	✓
splice	✓	Partially implement without inserting items
toLocaleString
toString	✓
unshift	✓
values
[Symbol.iterator]
TypedArray
BYTES_PER_ELEMENT	✓
buffer	✓
byteLength	✓
byteOffset	✓
length	✓
from
of
copyWithin
entries
every	✓	No closures yet
fill	✓
filter
find
findIndex	✓	No closures yet
forEach
includes
indexOf
join
keys
lastIndexOf
map	✓	No closures yet
reduce	✓	No closures yet
reduceRight	✓	No closures yet
reverse
set
slice
some	✓	No closures yet
sort	✓
subarray	✓
toLocaleString
toString
values
[Symbol.iterator]
ArrayBuffer
byteLength	✓
isView	✓
slice	✓
transfer		Stage 2 Proposal
toString	✓
DataView	✓
buffer	✓
byteLength	✓
byteOffset	✓
getInt8	✓
getUint8	✓
getInt16	✓
getUint16	✓
getInt32	✓
getUint32	✓
getInt64	✓	AssemblyScript specific
getUint64	✓	AssemblyScript specific
getFloat32	✓
getFloat64	✓
setInt8	✓
setUint8	✓
setInt16	✓
setUint16	✓
setInt32	✓
setUint32	✓
setInt64	✓	AssemblyScript specific
setUint64	✓	AssemblyScript specific
setFloat32	✓
setFloat64	✓
toString	✓
String
length	✓
lengthUTF8	✓	AssemblyScript specific
fromCharCode	✓
fromCharCodes	✓	AssemblyScript specific
fromCodePoint	✓
fromCodePoints	✓	AssemblyScript specific
fromUTF8	✓	AssemblyScript specific
charAt	✓
charCodeAt	✓
concat	✓
endsWith	✓
includes	✓
indexOf	✓
lastIndexOf	✓
localeCompare
match
normalize
padEnd	✓
padStart	✓
repeat	✓
replace
replaceAll		Stage 1 Proposal
search
slice	✓
split	✓
startsWith	✓
substr	✓
substring	✓
toLocaleLowerCase
toLocaleUpperCase
toLowerCase
toUpperCase
toString	✓
toUTF8	✓	AssemblyScript specific
trim	✓
trimLeft/trimStart	✓
trimRight/trimEnd	✓
[Symbol.iterator]
raw
Symbol	✓
for	✓
keyFor	✓
toString	✓
Math		This also applies to specific Mathf (single float point) version of Math
E	✓
LN10	✓
LN2	✓
LOG10E	✓
LOG2E	✓
PI	✓
SQRT1_2	✓
SQRT2	✓
abs	✓
acos	✓
acosh	✓
asin	✓
asinh	✓
atan	✓
atan2	✓
atanh	✓
cbrt	✓
ceil	✓
clz32	✓
cos
cosh	✓
exp	✓
expm1	✓
floor	✓
fround	✓
hypot	✓
imul	✓
log	✓
log10	✓
log1p	✓
log2	✓
max	✓
min	✓
pow	✓
random	✓
round	✓
sign	✓
signbit	✓	Stage 1 Proposal
sin
sincos		AssemblyScript specific
sinh	✓
sqrt	✓
tan
tanh	✓
trunc	✓
Map
size	✓
clear	✓
delete	✓
entries
forEach
get	✓
has	✓
set	✓
keys
values
toString	✓
[Symbol.iterator]
Set
size	✓
add	✓
clear	✓
delete	✓
difference		Stage 2 Proposal
entries
forEach
has	✓
intersection		Stage 2 Proposal
isDisjointFrom		Stage 2 Proposal
isSubsetOf		Stage 2 Proposal
isSupersetOf		Stage 2 Proposal
union		Stage 2 Proposal
symmetricDifference		Stage 2 Proposal
values
toString	✓
[Symbol.iterator]
WeakMap
delete
get
has
set
toString
WeakSet
add
delete
has
toString
Console
assert
clear
count
countReset
dir
error
group
groupCollapsed
groupEnd
info
log
table
time
timeEnd
trace
warn
JSON
parse
stringify
Object
is
keys
assign
create
entries
getOwnPropertyNames
getOwnPropertySymbols
toString
values
Date
UTC	✓
now	✓
parse
getDate
getDay
getFullYear
getHours
getMilliseconds
getMinutes
getMonth
getSeconds
getTime	✓
getTimezoneOffset
getUTCDate
getUTCDay
getUTCFullYear
getUTCHours
getUTCMilliseconds
getUTCMinutes
getUTCMonth
getUTCSeconds
setDate
setFullYear
setHours
setMilliseconds
setMinutes
setMonth
setSeconds
setTime	✓
setUTCDate
setUTCFullYear
setUTCHours
setUTCMilliseconds
setUTCMinutes
setUTCMonth
setUTCSeconds
toDateString
toISOString
toJSON
toLocaleDateString
toLocaleString
toLocaleTimeString
toString
toTimeString
toUTCString
Error
message	✓
name	✓
stack
toString	✓
Iterator
collect		Iterator helpers proposal (Stage 1)
from		Iterator helpers proposal (Stage 1)
filter		Iterator helpers proposal (Stage 1)
of		Iterator helpers proposal (Stage 1)
map		Iterator helpers proposal (Stage 1)
next
reduce		Iterator helpers proposal (Stage 1)
return
take		Iterator helpers proposal (Stage 1)
throw
Promise
all
allSettled		Stage 2
race
reject
resolve
catch
finally
then
RegExp
$1-$9
input ($_)
lastMatch ($&)
lastParen ($+)
lastIndex
leftContext ($`)
rightContext ($')
flags
global
ignoreCase
multiline
source
sticky
unicode
exec
test
toSource
toString
[Symbol.replace]
[Symbol.search]
[Symbol.split]
Atomics
add
and
compareExchange
exchange
isLockFree
load
notify
or
store
sub
wait
wake
xor
SIMD (v128)
const
splat
extract_lane(_u/_s)
replace_lane
shuffle
add
sub
mul
neg
add_saturate_(u/s)
sub_saturate_(u/s)
shl
shr_(u/s)
and
or
xor
not
bitselect
any_true
all_true
eq
ne
lt(_u/_s)
le(_u/_s)
gt(_u/_s)
ge(_u/_s)
load
store
abs
min
max
div		Only f32x4/f64x2
sqrt		Only f32x4/f64x2
convert_(u/s)
trunc_(u/s)

BigInt