Original QuickJS Notes

[shiqimei]

TODO

Bugs: - modules: better error handling with cyclic module references

Misc ideas:

• use custom printf to avoid compatibility issues with floating point numbers
• consistent naming for preprocessor defines
• unify coding style and naming conventions
• use names from the ECMA spec in library implementation
• use byte code emitters with typed arguments (for clarity)
• use 2 bytecode DynBufs in JSFunctionDef, one for reading, one for writing
  and use the same wrappers in all phases
• use more generic method for line numbers in resolve_variables and resolve_labels
• use custom timezone support to avoid C library compatibility issues

Memory:

• use memory pools for objects, etc?
• test border cases for max number of atoms, object properties, string length
• add emergency malloc mode for out of memory exceptions.
• test all DynBuf memory errors
• test all js_realloc memory errors
• improve JS_ComputeMemoryUsage() with more info

Built-in standard library:

• BSD sockets
• modules: use realpath in module name normalizer and put it in quickjs-libc
• modules: if no ".", use a well known module loading path ?
• get rid of __loadScript, use more common name

REPL:

• debugger
• readline: support MS Windows terminal
• readline: handle dynamic terminal resizing
• readline: handle double width unicode characters
• multiline editing
• runtime object and function inspectors
• interactive object browser
• use more generic approach to display evaluation results
• improve directive handling: dispatch, colorize, completion...
• save history
• close all predefined methods in repl.js and jscalc.js

Optimization ideas:

• 64-bit atoms in 64-bit mode ?
• 64-bit small bigint in 64-bit mode ?
• reuse stack slots for disjoint scopes, if strip
• add heuristic to avoid some cycles in closures
• small String (0-2 charcodes) with immediate storage
• perform static string concatenation at compile time
• optimize string concatenation with ropes or miniropes?
• add implicit numeric strings for Uint32 numbers?
• optimize s += a + b, s += a.b and similar simple expressions
• ensure string canonical representation and optimise comparisons and hashes?
• remove JSObject.first_weak_ref, use bit+context based hashed array for weak references
• property access optimization on the global object, functions,
  prototypes and special non extensible objects.
• create object literals with the correct length by backpatching length argument
• remove redundant set_loc_uninitialized/check_uninitialized opcodes
• peephole optim: push_atom_value, to_propkey -> push_atom_value
• peephole optim: put_loc x, get_loc_check x -> set_loc x
• convert slow array to fast array when all properties != length are numeric
• optimize destructuring assignments for global and local variables
• implement some form of tail-call-optimization
• optimize OP_apply
• optimize f(...b)

Test262o: 0/11262 errors, 463 excluded
Test262o commit: 7da91bceb9ce7613f87db47ddd1292a2dda58b42 (es5-tests branch)

Result: 35/75280 errors, 909 excluded, 585 skipped
Test262 commit: 31126581e7290f9233c29cefd93f66c6ac78f1c9

VERSION

2021-03-27

Changelog

2021-03-27:

• faster Array.prototype.push and Array.prototype.unshift
• added JS_UpdateStackTop()
• fixed Windows console
• misc bug fixes

2020-11-08:

• improved function parameter initializers
• added std.setenv(), std.unsetenv() and std.getenviron()
• added JS_EvalThis()
• misc bug fixes

2020-09-06:

• added logical assignment operators
• added IsHTMLDDA support
• faster for-of loops
• os.Worker now takes a module filename as parameter
• qjsc: added -D option to compile dynamically loaded modules or workers
• misc bug fixes

2020-07-05:

• modified JS_GetPrototype() to return a live value
• REPL: support unicode characters larger than 16 bits
• added os.Worker
• improved object serialization
• added std.parseExtJSON
• misc bug fixes

2020-04-12:

• added cross realm support
• added AggregateError and Promise.any
• added env, uid and gid options in os.exec()
• misc bug fixes

2020-03-16:

• reworked error handling in std and os libraries: suppressed I/O
  exceptions in std FILE functions and return a positive errno value
  when it is explicit
• output exception messages to stderr
• added std.loadFile(), std.strerror(), std.FILE.prototype.tello()
• added JS_GetRuntimeOpaque(), JS_SetRuntimeOpaque(), JS_NewUint32()
• updated to Unicode 13.0.0
• misc bug fixes

2020-01-19:

• keep CONFIG_BIGNUM in the makefile
• added os.chdir()
• qjs: added -I option
• more memory checks in the bignum operations
• modified operator overloading semantics to be closer to the TC39
  proposal
• suppressed "use bigint" mode. Simplified "use math" mode
• BigDecimal: changed suffix from 'd' to 'm'
• misc bug fixes

2020-01-05:

• always compile the bignum code. Added '--bignum' option to qjs.
• added BigDecimal
• added String.prototype.replaceAll
• misc bug fixes

2019-12-21:

• added nullish coalescing operator (ES2020)
• added optional chaining (ES2020)
• removed recursions in garbage collector
• test stack overflow in the parser
• improved backtrace logic
• added JS_SetHostPromiseRejectionTracker()
• allow exotic constructors
• improved c++ compatibility
• misc bug fixes

2019-10-27:

• added example of C class in a module (examples/test_point.js)
• added JS_GetTypedArrayBuffer()
• misc bug fixes

2019-09-18:

• added os.exec and other system calls
• exported JS_ValueToAtom()
• qjsc: added 'qjsc_' prefix to the generated C identifiers
• added cross-compilation support
• misc bug fixes

2019-09-01:

• added globalThis
• documented JS_EVAL_FLAG_COMPILE_ONLY
• added import.meta.url and import.meta.main
• added 'debugger' statement
• misc bug fixes

2019-08-18:

• added os.realpath, os.getcwd, os.mkdir, os.stat, os.lstat,
  os.readlink, os.readdir, os.utimes, std.popen
• module autodetection
• added import.meta
• misc bug fixes

2019-08-10:

• added public class fields and private class fields, methods and
  accessors (TC39 proposal)
• changed JS_ToCStringLen() prototype
• qjsc: handle '-' in module names and modules with the same filename
• added std.urlGet
• exported JS_GetOwnPropertyNames() and JS_GetOwnProperty()
• exported some bigint C functions
• added support for eshost in run-test262
• misc bug fixes

2019-07-28:

• added dynamic import
• added Promise.allSettled
• added String.prototype.matchAll
• added Object.fromEntries
• reduced number of ticks in await
• added BigInt support in Atomics
• exported JS_NewPromiseCapability()
• misc async function and async generator fixes
• enabled hashbang support by default

2019-07-21:

• updated test262 tests
• updated to Unicode version 12.1.0
• fixed missing Date object in qjsc
• fixed multi-context creation
• misc ES2020 related fixes
• simplified power and division operators in bignum extension
• fixed several crash conditions

2019-07-09:

• first public release