Fix spec conformity in corner case 'for await (async of ...)'.
## 8.2.3 (2021-05-04)
### Bug fixes
Fix an issue where the library couldn't parse 'for (async of ...)'.
Fix a bug in UTF-16 decoding that would read characters incorrectly in some circumstances.
## 8.2.2 (2021-04-29)
### Bug fixes
Fix a bug where a class field initialized to an async arrow function wouldn't allow await inside it. Same issue existed for generator arrow functions with yield.
## 8.2.1 (2021-04-24)
### Bug fixes
Fix a regression introduced in 8.2.0 where static or async class methods with keyword names fail to parse.
## 8.2.0 (2021-04-24)
### New features
Add support for ES2022 class fields and private methods.
## 8.1.1 (2021-04-12)
### Various
Stop shipping source maps in the NPM package.
## 8.1.0 (2021-03-09)
### Bug fixes
Fix a spurious error in nested destructuring arrays.
### New features
Expose `allowAwaitOutsideFunction` in CLI interface.
Make `allowImportExportAnywhere` also apply to `import.meta`.
## 8.0.5 (2021-01-25)
### Bug fixes
Adjust package.json to work with Node 12.16.0 and 13.0-13.6.
## 8.0.4 (2020-10-05)
### Bug fixes
Make `await x ** y` an error, following the spec.
Fix potentially exponential regular expression.
## 8.0.3 (2020-10-02)
### Bug fixes
Fix a wasteful loop during `Parser` creation when setting `ecmaVersion` to `"latest"`.
## 8.0.2 (2020-09-30)
### Bug fixes
Make the TypeScript types reflect the current allowed values for `ecmaVersion`.
Fix another regexp/division tokenizer issue.
## 8.0.1 (2020-08-12)
### Bug fixes
Provide the correct value in the `version` export.
## 8.0.0 (2020-08-12)
### Bug fixes
Disallow expressions like `(a = b) = c`.
Make non-octal escape sequences a syntax error in strict mode.
### New features
The package can now be loaded directly as an ECMAScript module in node 13+.
Update to the set of Unicode properties from ES2021.
### Breaking changes
The `ecmaVersion` option is now required. For the moment, omitting it will still work with a warning, but that will change in a future release.
Some changes to method signatures that may be used by plugins.
## 7.4.0 (2020-08-03)
### New features
Add support for logical assignment operators.
Add support for numeric separators.
## 7.3.1 (2020-06-11)
### Bug fixes
Make the string in the `version` export match the actual library version.
## 7.3.0 (2020-06-11)
### Bug fixes
Fix a bug that caused parsing of object patterns with a property named `set` that had a default value to fail.
### New features
Add support for optional chaining (`?.`).
## 7.2.0 (2020-05-09)
### Bug fixes
Fix precedence issue in parsing of async arrow functions.
### New features
Add support for nullish coalescing.
Add support for `import.meta`.
Support `export * as ...` syntax.
Upgrade to Unicode 13.
## 6.4.1 (2020-03-09)
### Bug fixes
More carefully check for valid UTF16 surrogate pairs in regexp validator.
## 7.1.1 (2020-03-01)
### Bug fixes
Treat `\8` and `\9` as invalid escapes in template strings.
Allow unicode escapes in property names that are keywords.
Don't error on an exponential operator expression as argument to `await`.
More carefully check for valid UTF16 surrogate pairs in regexp validator.
## 7.1.0 (2019-09-24)
### Bug fixes
Disallow trailing object literal commas when ecmaVersion is less than 5.
### New features
Add a static `acorn` property to the `Parser` class that contains the entire module interface, to allow plugins to access the instance of the library that they are acting on.
## 7.0.0 (2019-08-13)
### Breaking changes
Changes the node format for dynamic imports to use the `ImportExpression` node type, as defined in [ESTree](https://github.com/estree/estree/blob/master/es2020.md#importexpression).
Makes 10 (ES2019) the default value for the `ecmaVersion` option.
## 6.3.0 (2019-08-12)
### New features
`sourceType: "module"` can now be used even when `ecmaVersion` is less than 6, to parse module-style code that otherwise conforms to an older standard.
## 6.2.1 (2019-07-21)
### Bug fixes
Fix bug causing Acorn to treat some characters as identifier characters that shouldn't be treated as such.
Fix issue where setting the `allowReserved` option to `"never"` allowed reserved words in some circumstances.
## 6.2.0 (2019-07-04)
### Bug fixes
Improve valid assignment checking in `for`/`in` and `for`/`of` loops.
Disallow binding `let` in patterns.
### New features
Support bigint syntax with `ecmaVersion` >= 11.
Support dynamic `import` syntax with `ecmaVersion` >= 11.
Upgrade to Unicode version 12.
## 6.1.1 (2019-02-27)
### Bug fixes
Fix bug that caused parsing default exports of with names to fail.
## 6.1.0 (2019-02-08)
### Bug fixes
Fix scope checking when redefining a `var` as a lexical binding.
### New features
Split up `parseSubscripts` to use an internal `parseSubscript` method to make it easier to extend with plugins.
## 6.0.7 (2019-02-04)
### Bug fixes
Check that exported bindings are defined.
Don't treat `\u180e` as a whitespace character.
Check for duplicate parameter names in methods.
Don't allow shorthand properties when they are generators or async methods.
Forbid binding `await` in async arrow function's parameter list.
## 6.0.6 (2019-01-30)
### Bug fixes
The content of class declarations and expressions is now always parsed in strict mode.
Don't allow `let` or `const` to bind the variable name `let`.
Treat class declarations as lexical.
Don't allow a generator function declaration as the sole body of an `if` or `else`.
Ignore `"use strict"` when after an empty statement.
Allow string line continuations with special line terminator characters.
Treat `for` bodies as part of the `for` scope when checking for conflicting bindings.
Fix bug with parsing `yield` in a `for` loop initializer.
Implement special cases around scope checking for functions.
## 6.0.5 (2019-01-02)
### Bug fixes
Fix TypeScript type for `Parser.extend` and add `allowAwaitOutsideFunction` to options type.
Don't treat `let` as a keyword when the next token is `{` on the next line.
Fix bug that broke checking for parentheses around an object pattern in a destructuring assignment when `preserveParens` was on.
## 6.0.4 (2018-11-05)
### Bug fixes
Further improvements to tokenizing regular expressions in corner cases.
## 6.0.3 (2018-11-04)
### Bug fixes
Fix bug in tokenizing an expression-less return followed by a function followed by a regular expression.
Remove stray symlink in the package tarball.
## 6.0.2 (2018-09-26)
### Bug fixes
Fix bug where default expressions could fail to parse inside an object destructuring assignment expression.
## 6.0.1 (2018-09-14)
### Bug fixes
Fix wrong value in `version` export.
## 6.0.0 (2018-09-14)
### Bug fixes
Better handle variable-redefinition checks for catch bindings and functions directly under if statements.
Forbid `new.target` in top-level arrow functions.
Fix issue with parsing a regexp after `yield` in some contexts.
### New features
The package now comes with TypeScript definitions.
### Breaking changes
The default value of the `ecmaVersion` option is now 9 (2018).
Plugins work differently, and will have to be rewritten to work with this version.
The loose parser and walker have been moved into separate packages (`acorn-loose` and `acorn-walk`).
## 5.7.3 (2018-09-10)
### Bug fixes
Fix failure to tokenize regexps after expressions like `x.of`.
Better error message for unterminated template literals.
## 5.7.2 (2018-08-24)
### Bug fixes
Properly handle `allowAwaitOutsideFunction` in for statements.
Treat function declarations at the top level of modules like let bindings.
Don't allow async function declarations as the only statement under a label.
## 5.7.0 (2018-06-15)
### New features
Upgraded to Unicode 11.
## 5.6.0 (2018-05-31)
### New features
Allow U+2028 and U+2029 in string when ECMAVersion >= 10.
Allow binding-less catch statements when ECMAVersion >= 10.
Add `allowAwaitOutsideFunction` option for parsing top-level `await`.
## 5.5.3 (2018-03-08)
### Bug fixes
A _second_ republish of the code in 5.5.1, this time with yarn, to hopefully get valid timestamps.
## 5.5.2 (2018-03-08)
### Bug fixes
A republish of the code in 5.5.1 in an attempt to solve an issue with the file timestamps in the npm package being 0.
## 5.5.1 (2018-03-06)
### Bug fixes
Fix misleading error message for octal escapes in template strings.
## 5.5.0 (2018-02-27)
### New features
The identifier character categorization is now based on Unicode version 10.
Acorn will now validate the content of regular expressions, including new ES9 features.
## 5.4.0 (2018-02-01)
### Bug fixes
Disallow duplicate or escaped flags on regular expressions.
Disallow octal escapes in strings in strict mode.
### New features
Add support for async iteration.
Add support for object spread and rest.
## 5.3.0 (2017-12-28)
### Bug fixes
Fix parsing of floating point literals with leading zeroes in loose mode.
Allow duplicate property names in object patterns.
Don't allow static class methods named `prototype`.
Disallow async functions directly under `if` or `else`.
Parse right-hand-side of `for`/`of` as an assignment expression.
Stricter parsing of `for`/`in`.
Don't allow unicode escapes in contextual keywords.
### New features
Parsing class members was factored into smaller methods to allow plugins to hook into it.
Fix token context tracking for `class` and `function` in property-name position.
Make sure `%*` isn't parsed as a valid operator.
Allow shorthand properties `get` and `set` to be followed by default values.
Disallow `super` when not in callee or object position.
### New features
Support [`directive` property](https://github.com/estree/estree/compare/b3de58c9997504d6fba04b72f76e6dd1619ee4eb...1da8e603237144f44710360f8feb7a9977e905e0) on directive expression statements.
## 5.1.2 (2017-09-04)
### Bug fixes
Disable parsing of legacy HTML-style comments in modules.
Fix parsing of async methods whose names are keywords.
## 5.1.1 (2017-07-06)
### Bug fixes
Fix problem with disambiguating regexp and division after a class.
## 5.1.0 (2017-07-05)
### Bug fixes
Fix tokenizing of regexps in an object-desctructuring `for`/`of` loop and after `yield`.
Parse zero-prefixed numbers with non-octal digits as decimal.
Allow object/array patterns in rest parameters.
Don't error when `yield` is used as a property name.
Allow `async` as a shorthand object property.
### New features
Implement the [template literal revision proposal](https://github.com/tc39/proposal-template-literal-revision) for ES9.
## 5.0.3 (2017-04-01)
### Bug fixes
Fix spurious duplicate variable definition errors for named functions.
## 5.0.2 (2017-03-30)
### Bug fixes
A binary operator after a parenthesized arrow expression is no longer incorrectly treated as an error.
## 5.0.0 (2017-03-28)
### Bug fixes
Raise an error for duplicated lexical bindings.
Fix spurious error when an assignement expression occurred after a spread expression.
Accept regular expressions after `of` (in `for`/`of`), `yield` (in a generator), and braced arrow functions.
Allow labels in front or `var` declarations, even in strict mode.
### Breaking changes
Parse declarations following `export default` as declaration nodes, not expressions. This means that class and function declarations nodes can now have `null` as their `id`.
## 4.0.11 (2017-02-07)
### Bug fixes
Allow all forms of member expressions to be parenthesized as lvalue.
Solve spurious parenthesized pattern errors by temporarily erring on the side of accepting programs that our delayed errors don't handle correctly yet.