Letting these create and return a JS::Array directly is pretty awkward
since we then need to go through the indexed properties for iteration.
Just use a MarkedValueList (i.e. Vector<Value>) for this and add a new
Array::create_from() function to turn the Vector into a returnable
Array as we did before.
This brings it a lot closer to the spec as well, which uses the
CreateArrayFromList abstract operation to do exactly this.
There's an optimization opportunity for the future here, since we know
the Vector's size we could prepare the newly created Array accordingly,
e.g. by switching to generic storage upfront if needed.
The new default return_type argument is GetOwnPropertyReturnType::All,
which returns properties with both string and symbol keys (which is also
the default for [[OwnPropertyKeys]]). This means that in some cases we
need to iterate the ordered property table twice, as we don't store
string and symbol properties separately but symbols must - there's
certainly room for (performance) improvements here. On the other hand
this makes Reflect.ownKeys() return symbol properties now :^)
Object::get_own_properties() is a bit unwieldy to use - especially as
StringOnly is about to no longer be the default value. The spec has an
abstract operation specifically for this (EnumerateObjectProperties),
so let's use that. No functionality change.
Specifically:
- Object::get_own_properties()
- Object::put_own_property()
- Object::put_own_property_by_index()
These APIs make no sense (and are inconsistent, get_own_property()
didn't have this parameter, for example) - and as expected we were
always passing in the same object we were calling the method on anyway.
This was super confusing as we would check if the exception's value is a
JS::Error and not log it otherwise, even with m_should_log_exceptions
set.
As a result, things like DOM exceptions were invisible to us with
execution just silently stopping, for example.
Not sure if this regressed at some point or just never worked, it
definitely wasn't tested at all. We would always return undefined when
returning from a try statement block, handler, or finalizer.
By using regex::AllFlags::SkipTrimEmptyMatches we get a null string for
unmatched capture groups, which we then turn into an undefined entry in
the result array instead of putting all matches first and appending
undefined for the remaining number of capture groups - e.g. for
/foo(ba((r)|(z)))/.exec("foobaz")
we now return
["foobaz", "baz", "z", undefined, "z"]
and not [
["foobaz", "baz", "z", "z", undefined]
Fixes part of #6042.
Also happens to fix selecting an element by ID using jQuery's $("#foo").
This fixes an issue where `undefined.foo = "bar"` would throw a
ReferenceError instead of a TypeError as undefined was also used for
truly unresolvable references (e.g. `foo() = "bar"`). I also made the
various error messages here a bit nicer, just "primitive value" is not
very helpful.
We should be able to get the 'typeof' string for any value directly, so
this is now a standalone Value::typeof() method instead of being part of
UnaryExpression::execute().
Almost a year after first working on this, it's finally done: an
implementation of Promises for LibJS! :^)
The core functionality is working and closely following the spec [1].
I mostly took the pseudo code and transformed it into C++ - if you read
and understand it, you will know how the spec implements Promises; and
if you read the spec first, the code will look very familiar.
Implemented functions are:
- Promise() constructor
- Promise.prototype.then()
- Promise.prototype.catch()
- Promise.prototype.finally()
- Promise.resolve()
- Promise.reject()
For the tests I added a new function to test-js's global object,
runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs().
By design, queued jobs normally only run after the script was fully
executed, making it improssible to test handlers in individual test()
calls by default [2].
Subsequent commits include integrations into LibWeb and js(1) -
pretty-printing, running queued promise jobs when necessary.
This has an unusual amount of dbgln() statements, all hidden behind the
PROMISE_DEBUG flag - I'm leaving them in for now as they've been very
useful while debugging this, things can get quite complex with so many
asynchronously executed functions.
I've not extensively explored use of these APIs for promise-based
functionality in LibWeb (fetch(), Notification.requestPermission()
etc.), but we'll get there in due time.
[1]: https://tc39.es/ecma262/#sec-promise-objects
[2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
This only applies to the ECMA262 parser.
This behaviour is an ECMA262-specific quirk, such references always
generate zero-length matches (even on subsequent passes).
Also adds a test in LibJS's test suite.
Fixes#6039.
The test-js program expects this to exist for 'result: "fail"' results
and would crash if any duplicated test(message) occurs, as we didn't
provide 'details' in that case.
1. Allow Value(size_t) and use it for array length properties.
If an array length can't fit in an Int32 value, we shouldn't go out of
or way to force it into one. Instead, for values above INT32_MAX,
we simply store them as Double values.
2. Switch to generic indexed property storage for large arrays.
Previously we would always allocate array storage eagerly when the
length property was set. This meant that "a.length = 0x80000000" would
trivially DOS the engine on 32-bit since we don't have that much VM.
We now switch to generic storage when changing the length moves us over
the 4M entry mark.
Fixes#5986.
Just a sanity check, this must never happen. Manual invocations of
call() e.g. in LibWeb bindings must pass js_undefined() if no specific
this value is desired, which OrdinaryCallBindThis will then use as-is or
turn into the global this value in non-strict mode.
This commit replaces the usage of String::starts_with with
Utf8View::starts_with, which first decodes the utf8 encoded
string, and as such can take things like overlong encoded
sequences into account (which could otherwise cause the prefix
check to be inconsistent with the following code points check).
Since we have Value::Type::Int32 now, let's use the Value(i32)
constructor here directly by not casting these i32 values to doubles.
The Value(double) would also figure out that these can be stored as
integers, but needs to do extra work which is not needed here. :^)
Just like to_size_t() - which was already removed in f369229 - this is
non-standard, use to_length() instead. One remaining use was removed,
and I'm glad it's gone. :^)
toGMTString() is deprecated but is kept for compatibility's sake, but because
HTTP Dates are always expressed in GMT, it should be safe to call toUTCString()
in toGMTString().
The auto naming of function expressions is a purely syntactic
decision, so shouldn't be decided based on the dynamic type of
an assignment. This moves the decision making into the parser.
One icky hack is that we add a field to FunctionExpression to
indicate whether we can autoname. The real solution is to actually
generate a CompoundExpression node so that the parser can make
the correct decision, however this would have a potentially
significant run time cost.
This does not correct the behaviour for class expressions.
Patch from Anonymous.
As @nico pointed out, 0.0 == -0.0 in C++, even though they are not
bitwise identical. Use the same trick as Value::is_negative_zero() to
really check for it.
This allows JS::Value(0.0) to correctly become an Int32-backed 0 value.
We now store 32-bit integers as 32-bit integers directly which avoids
having to convert them from doubles when they're only used as 32-bit
integers anyway. :^)
This patch feels a bit incomplete and there's a lot of opportunities
to take advantage of this information. We'll have to find and exploit
them eventually.
Previously we would generate function names for anonymous functions
on every AssignmentExpression, even if we weren't assigning a function.
We were also setting names of anonymous functions in arrays, which is
apparently a SpiderMonkey specific behavior not supported by V8, JSC
or required by ECMA262. This patch removes that behavior.
This is a huge performance improvement on the CanvasCycle demo! :^)
This patch rethinks the way indexed property storage works:
Instead of having a cut-off point at 200 elements where we always move
to generic property storage, we now allow arrays to stay in simple mode
as long as we don't create a gap/hole larger than 200 elements.
We also simplify generic storage to only have a hash map (for now)
instead of juggling both a vector and a hash map. This is mostly fine
since the vast majority of arrays get to stay simple now.
This is a huge speedup on anything that uses basic JS arrays with more
than 200 elements in them. :^)
Otherwise we continuously lose the first sparse element (at index
SPARSE_ARRAY_THRESHOLD) without noticing, as we overwrite all indices
with the value at index+1.
Fixes#5884.
