Implement new get_or_undefined method for [JsValue]

[jedel1043]

This Pull Request fixes/closes #1490.

It changes the following:

• Adds a new trait JsArgs to add new methods to [JsValue]
• Implements a new method get_or_undefined for [JsValue]
• Replaces calls to args.get(n).cloned().unwrap_or_default() with args.get_or_undefined()

This should improve the usability of the api by not having to unwrap_or_default everytime we want an argument inside a builtin function.

[Razican]

Hmmm I'm not sure if the extra trait and code improves the ergonomic enough to stoping using well known standard library APIs and adding a new trait.

I would like to know the thoughts of more people.

[RageKnify]

If we are to do something like this I think returning a reference would be better, that way we would be reducing the number of clones.
To get the reference to undefined it might work to have a constant? Not sure if it's possible, but if so I think it'd be a nice solution.
We'd have const undefined: Value = Value::Undefined; in the trait's file and then we can use a reference to it in the method.

[jedel1043]

Hmmm I'm not sure if the extra trait and code improves the ergonomic enough to stoping using well known standard library APIs and adding a new trait.

Completely understandable. I just wanted to point out that you can still use get as always without any problem; there are a lot of uses of get without defaulting to undefined. This is just a utility function to simplify a common action that appears 60+ times in the codebase.

[jedel1043]

If we are to do something like this I think returning a reference would be better, that way we would be reducing the number of clones.
To get the reference to undefined it might work to have a constant? Not sure if it's possible, but if so I think it'd be a nice solution.
We'd have const undefined: Value = Value::Undefined; in the trait's file and then we can use a reference to it in the method.

Let me try this. I tried to use a Cow but the performance was worse than cloning, so i opted for the clone. A const if its possible or a static if it isn't should do the trick.

[Razican]

┌─────────┬──────────────────────────────────────────────┬────────────────────┬─────────────────────┬────────────┐
│ (index) │                     name                     │  changesDuration   │   masterDuration    │ difference │
├─────────┼──────────────────────────────────────────────┼────────────────────┼─────────────────────┼────────────┤
│    0    │     'Arithmetic operations (Execution)'      │   '228.6±0.33ns'   │ '**221.5±0.46ns**'  │   '+3.0'   │
│    1    │        'Arithmetic operations (Full)'        │ '**263.7±0.46µs**' │   '266.1±0.49µs'    │  '-0.99'   │
│    2    │          'Array access (Execution)'          │  '**5.0±0.02µs**'  │    '5.8±0.02µs'     │   '-13'    │
│    3    │            'Array access (Full)'             │   '288.5±0.49µs'   │   '287.3±0.50µs'    │   '0.0'    │
│    4    │         'Array creation (Execution)'         │  '**2.2±0.01ms**'  │    '2.7±0.00ms'     │   '-18'    │
│    5    │           'Array creation (Full)'            │    '2.9±0.00ms'    │  '**2.7±0.00ms**'   │   '+10'    │
│    6    │           'Array pop (Execution)'            │ '**816.0±2.49µs**' │   '863.8±2.42µs'    │   '-5.7'   │
│    7    │              'Array pop (Full)'              │  '1280.0±1.12µs'   │ '**1213.2±1.42µs**' │   '+6.0'   │
│    8    │     'Boolean Object Access (Execution)'      │  '**4.6±0.01µs**'  │    '4.6±0.01µs'     │  '-0.99'   │
│    9    │        'Boolean Object Access (Full)'        │   '282.8±0.35µs'   │   '281.7±0.36µs'    │   '0.0'    │
│   10    │            'Clean js (Execution)'            │ '**624.6±3.57µs**' │   '637.9±3.52µs'    │   '-2.0'   │
│   11    │              'Clean js (Full)'               │   '939.3±3.08µs'   │ '**930.7±3.05µs**'  │   '+1.0'   │
│   12    │             'Clean js (Parser)'              │ '**31.0±0.04µs**'  │    '31.3±0.15µs'    │  '-0.99'   │
│   13    │                'Create Realm'                │ '**312.4±0.51ns**' │   '349.6±1.77ns'    │   '-11'    │
│   14    │ 'Dynamic Object Property Access (Execution)' │  '**3.9±0.02µs**'  │    '4.5±0.01µs'     │   '-13'    │
│   15    │   'Dynamic Object Property Access (Full)'    │   '285.8±0.44µs'   │   '286.2±1.20µs'    │   '0.0'    │
│   16    │            'Expression (Parser)'             │    '5.2±0.01µs'    │    '5.2±0.02µs'     │   '0.0'    │
│   17    │           'Fibonacci (Execution)'            │   '687.8±2.98µs'   │ '**677.5±0.67µs**'  │   '+2.0'   │
│   18    │              'Fibonacci (Full)'              │   '963.8±1.72µs'   │   '967.6±2.30µs'    │   '0.0'    │
│   19    │            'For loop (Execution)'            │ '**15.1±0.06µs**'  │    '17.0±0.07µs'    │   '-12'    │
│   20    │              'For loop (Full)'               │ '**290.3±1.53µs**' │   '294.1±0.37µs'    │  '-0.99'   │
│   21    │             'For loop (Parser)'              │   '14.7±0.05µs'    │    '14.8±0.01µs'    │   '0.0'    │
│   22    │           'Goal Symbols (Parser)'            │ '**10.6±0.01µs**'  │    '10.6±0.01µs'    │  '-0.99'   │
│   23    │            'Hello World (Parser)'            │    '3.0±0.02µs'    │    '3.0±0.01µs'     │   '0.0'    │
│   24    │             'Long file (Parser)'             │   '729.1±1.47ns'   │   '730.3±9.76ns'    │   '0.0'    │
│   25    │            'Mini js (Execution)'             │ '**572.2±4.35µs**' │   '585.1±3.88µs'    │   '-2.0'   │
│   26    │               'Mini js (Full)'               │   '885.2±2.57µs'   │ '**873.6±2.65µs**'  │   '+1.0'   │
│   27    │              'Mini js (Parser)'              │ '**27.4±0.03µs**'  │    '27.6±0.03µs'    │  '-0.99'   │
│   28    │      'Number Object Access (Execution)'      │    '3.7±0.01µs'    │    '3.6±0.01µs'     │   '0.0'    │
│   29    │        'Number Object Access (Full)'         │ '**276.3±0.34µs**' │   '277.9±0.43µs'    │  '-0.99'   │
│   30    │        'Object Creation (Execution)'         │  '**4.0±0.01µs**'  │    '4.0±0.02µs'     │  '-0.99'   │
│   31    │           'Object Creation (Full)'           │   '279.6±0.26µs'   │   '280.5±0.48µs'    │   '0.0'    │
│   32    │             'RegExp (Execution)'             │   '11.0±0.06µs'    │    '10.9±0.06µs'    │   '0.0'    │
│   33    │               'RegExp (Full)'                │ '**285.2±0.35µs**' │   '287.4±0.32µs'    │  '-0.99'   │
│   34    │         'RegExp Literal (Execution)'         │   '11.0±0.06µs'    │    '11.0±0.06µs'    │   '0.0'    │
│   35    │           'RegExp Literal (Full)'            │ '**292.2±1.80µs**' │   '294.3±0.30µs'    │  '-0.99'   │
│   36    │    'RegExp Literal Creation (Execution)'     │  '**7.2±0.03µs**'  │    '8.0±0.02µs'     │   '-11'    │
│   37    │       'RegExp Literal Creation (Full)'       │   '284.9±0.63µs'   │   '284.8±0.34µs'    │   '0.0'    │
│   38    │ 'Static Object Property Access (Execution)'  │  '**3.7±0.01µs**'  │    '4.2±0.02µs'     │   '-12'    │
│   39    │    'Static Object Property Access (Full)'    │   '281.3±0.53µs'   │   '281.0±0.50µs'    │   '0.0'    │
│   40    │      'String Object Access (Execution)'      │    '6.1±0.01µs'    │    '6.1±0.03µs'     │   '0.0'    │
│   41    │        'String Object Access (Full)'         │   '285.1±0.55µs'   │   '283.7±0.38µs'    │   '0.0'    │
│   42    │       'String comparison (Execution)'        │  '**5.3±0.01µs**'  │    '5.8±0.03µs'     │   '-9.9'   │
│   43    │          'String comparison (Full)'          │ '**281.2±1.45µs**' │   '287.0±2.68µs'    │   '-2.0'   │
│   44    │      'String concatenation (Execution)'      │  '**4.0±0.02µs**'  │    '4.5±0.02µs'     │   '-11'    │
│   45    │        'String concatenation (Full)'         │ '**275.9±2.82µs**' │   '280.3±0.44µs'    │   '-2.0'   │
│   46    │          'String copy (Execution)'           │  '**3.1±0.01µs**'  │    '3.6±0.01µs'     │   '-12'    │
│   47    │             'String copy (Full)'             │ '**270.9±0.35µs**' │   '273.5±0.44µs'    │  '-0.99'   │
│   48    │            'Symbols (Execution)'             │  '**2.7±0.03µs**'  │    '3.0±0.01µs'     │   '-9.1'   │
│   49    │               'Symbols (Full)'               │ '**261.7±0.55µs**' │   '264.0±2.52µs'    │  '-0.99'   │
│   50    │                      ''                      │     undefined      │      undefined      │   '+NaN'   │
└─────────┴──────────────────────────────────────────────┴────────────────────┴─────────────────────┴────────────┘

[Razican]

I'm OK with the changes :) I though we might have a performance improvement, but not really.

[jedel1043]

I'm OK with the changes :) I though we might have a performance improvement, but not really.

Still, there's a lot of small improvements in performance. The last version using clone was a lot slower.

[raskad]

Looks good!