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Acornima

1.8.010M downloads/moadams85/acornima ↗New releases in your daily digest, changelog included.

A standard-compliant JavaScript parser, which is a fork of Esprima.NET combined with the .NET port of the acornjs parser.

Last release 1 months ago
28 Aug 2026
Release timing varies
gaps range from 8 days to 8 months
Some releases are documented
notes for 11 of 19 stable releases
Nothing withdrawn
no release was ever pulled
3 years old
19 releases · first in 2024

Release timeline

19 releases since 2024

202420252026

Releases

1.8.028 Aug 2026
Introduce ParserOptions.AllowSuperCallOutsideConstructor to support PerformEval (see #44 ).
New features:

Introduce ParserOptions.AllowSuperCallOutsideConstructor to support PerformEval (see #44).

Bug fixes:

Fix ParserOptions.AllowSuperOutsideMethod to reject super property access in function contexts outside of classes (see #44 (comment)).

Fix regression that incorrectly allows super() in class fields when the class is declared inside another class's constructor (see #44 (comment)).

Fix legacy octal constructs not rejected in the token following an ASI-terminated "use strict" directive (see #49).

Fix legacy octal constructs being rejected right after a strict function body (see #51).

Fix early errors not raised in assignment patterns when the object literal is not refined into a pattern (see #52).
Open source →

Improvements:

Significant performance improvements to execution time and memory allocation (see #41, #42, #43 - big thanks to @lahma!):

Diff	Method	FileName	Mean	Error	Allocated
Old	AcornimaParse	angular-1.2.5	6,537.2 μs	41.25 μs	3970.92 KB
New			5,802.3 μs (-11%)	33.54 μs	3746.47 KB (-6%)
Old	AcornimaParse	angular-1.7.9	14,917.3 μs	200.57 μs	6719.28 KB
New			10,488.5 μs (-30%)	64.75 μs	6380.38 KB (-5%)
Old	AcornimaParse	backbone-1.1.0	806.5 μs	3.85 μs	628.3 KB
New			718.7 μs (-11%)	23.39 μs	585.99 KB (-7%)
Old	AcornimaParse	jquery-1.9.1	4,897.8 μs	67.04 μs	3263.86 KB
New			4,309.8 μs (-12%)	36.58 μs	3122.52 KB (-4%)
Old	AcornimaParse	jquery.mobile-1.4.2	8,620.0 μs	88.40 μs	5443.43 KB
New			7,329.0 μs (-15%)	75.73 μs	5231.79 KB (-4%)
Old	AcornimaParse	mootools-1.4.5	4,068.6 μs	33.49 μs	2750.82 KB
New			3,384.7 μs (-17%)	15.17 μs	2609.48 KB (-5%)
Old	AcornimaParse	underscore-1.5.2	695.8 μs	4.79 μs	528.92 KB
New			589.2 μs (-15%)	4.38 μs	500.55 KB (-5%)
Old	AcornimaParse	yui-3.12.0	3,693.0 μs	21.02 μs	2607.91 KB
New			3,282.1 μs (-11%)	4.38 μs	2466.57 KB (-5%)

Bug fixes:

Correct logic that detects non-compilable regular expression patterns.
Correct parser to properly report regular expression literal tokens via the OnToken callback for edge cases (see also acornjs/acorn#1443 (comment)).
Fix bug where ParenthesizedExpression is omitted from the AST when converting existing expressions to pattern nodes, despite enabling the PreserveParens option.
Correct parser to reject an unparenthesized arrow function as the left operand of exponentiation (see also acornjs/acorn#1450).
Correct AST to JS conversion to correctly parenthesize await expressions as the left side of exponentiation.
Correct JSX parser to properly handle edge cases (e.g., ({ *m() { yield <></> } }) and ({ async m() { await <></> } })).
Correct JSX parser to accept JSX elements after let/var/const line without terminating semicolon (see also acornjs/acorn-jsx#92).
Correct AST to JSX conversion to correctly handle fragments in unary and binary expressions.
Fix serialization error in Acornima.Cli's tokenizer mode.

Open source →

1.6.216 May 2026

Eliminate some unnecessary range checks and a few other micro-optimizations.

Improvements:

Eliminate some unnecessary range checks and a few other micro-optimizations.

Bug fixes:

Fix bug that leads to incorrect validation of ranges involving some escape sequences in character classes in flag v regexp patterns (i.e., in patterns like /[!-\#]/v).
Correct some syntax error locations in regexp patterns.
Correct cleanup of potentially large buffers in Tokenizer.AdaptRegExp and Tokenizer.ValidateRegExp.

Open source →

1.6.125 Apr 2026

Fix bug that disallows quantifier after modifier groups in flag v regexp patterns (i.e., in patterns like /(?i:x)?/v ).

Bug fixes:

Fix bug that disallows quantifier after modifier groups in flag v regexp patterns (i.e., in patterns like /(?i:x)?/v).
Fix error reporting for backslash at the end of regexp patterns.

Open source →

1.5.013 Apr 2026

Expose information about the parsed code to OnNode callbacks.

Improvements:

Expose information about the parsed code to OnNode callbacks.
Add the NotNullWhen attribute to the signature Tokenizer.ValidateRegExp to improve nullable static analysis.

Bug fixes:

Fix conversion of \w and \W character classes in regexp patterns. (U+0130 should not be matched.)
Fix conversion of the $ anchor in regexp patterns. (In .NET, \z should be used instead of $ to avoid matching before potential newline at the end of the input string.)
Fix validation of regexp patterns having a non-escaped backslash at the end.

Breaking changes:

Change the context parameter of ParserOptions.OnNode callbacks to be passed by-ref.

Open source →

1.4.010 Apr 2026Deprecated

The corresponding members in ExperimentalESFeatures have been deprecated as these features are now enabled for the related EcmaVersion compatibility l…

This release brings full support for ES2026.

The Import Attributes, Duplicate named capturing groups, Regular expression modifiers and Explicit resource management features are no longer experimental. The corresponding members in ExperimentalESFeatures have been deprecated as these features are now enabled for the related EcmaVersion compatibility levels by default.

A side note about regular expressions: For flag v patterns, only validation is supported. There are no plans to implement JS RegExp to .NET Regex conversion for flag v mode. Moreover, conversion logic for the other modes is going to be extracted into a separate library in v2.0. Therefore, this release deprecates regular expression conversion-related APIs but introduces new extension points (TokenizerOptions.OnRegExp and ParserOptions.OnRegExp) to take control over regular expression parsing if needed.

New features:

Introduce TokenizerOptions.OnRegExp and ParserOptions.OnRegExp as an alternative to TokenizerOptions.RegExpParseMode and ParserOptions.RegExpParseMode, respectively.

Improvements:

Update EcmaVersion to allow parsing against the recent ECMAScript standards, up to ES2026.
Implement (validation-only) support for flag v regular expressions (see #36).
Upgrade to Unicode 17.0 (see #36, #37).
Minor performance improvements (to execution time and heap allocations) around regular expression parsing.

Breaking changes:

Change the type of the RegExpParseResult.ConversionError property to ParseError.

Open source →

1.3.21 Apr 2026

Implement Annex B.3.9 ("Runtime Errors for Function Call Assignment Targets") (see acornjs/acorn#1433 , #33 )

Improvements:

Implement Annex B.3.9 ("Runtime Errors for Function Call Assignment Targets") (see acornjs/acorn#1433, #33)

Bug fixes:

Fix using/await using edge cases in for loops (see acornjs/acorn#1432, #31, #32)

Open source →

1.3.010 Mar 2026

Implement Regular Expression Modifiers as an experimental feature (see ExperimentalESFeatures.RegExpModifiers ).

New features:

Implement Regular Expression Modifiers as an experimental feature (see ExperimentalESFeatures.RegExpModifiers).

Improvements:

Minor performance-related tweaks.

Breaking changes:

Rename syntax error code DuplicateImportAttribute to ImportAttributesDuplicateKey to match V8 naming.
Remove syntax error code RegExpInvalidClassEscape as it is no longer reported.

Open source →

1.2.12 Mar 2026

Minor improvement to error reporting (adjust some RegExp-related error messages changed in V8 recently).

Improvements:

Minor improvement to error reporting (adjust some RegExp-related error messages changed in V8 recently).
Minor improvement to XML documentation.
Minor corrections to README.md.

Bug fixes:

Disallow the test of ConditionalExpression to be an unparenthesized ArrowFunctionExpression (see also acornjs/acorn#1428).

Open source →