ContextQMD
Back to Biome

Challenge report

crates/biome_js_formatter/report-challenge.md

latest7.7 KB
Original Source

Challenge report

Challenge: https://console.algora.io/challenges/prettier

We provide two compatibility reports for the challenge:

  • report-es215 that takes only ES2015 syntaxes into account;
  • report-es2024+ that takes ES2024 syntaxes into account and widely supported experimental syntaxes (decorators, import assertions, import attributes, explicit resource management).

You can test Biome directly on the playground, or using our latest nightly release.

sh
npm install -D @biomejs/[email protected]

Please find more details in our Getting Started guide.

Test case notes

Ignored test cases

report-es215 and report-es2024+ ignore the following test cases:

  • JSX

    • js/binary-expressions/inline-jsx.js
    • js/binary-expressions/jsx_parent.js
    • js/call/first-argument-expansion/jsx.js
    • js/comments-closure-typecast/styled-components.js
    • js/comments/html-like/
    • js/comments/jsx.js
    • js/comments/return-statement.js
    • js/last-argument-expansion/jsx.js
    • js/trailing-comma/jsx.js
    • js/throw_statement/jsx.js
    • js/unicode/nbsp-jsx.js
    • js/yield/jsx-without-parenthesis.js
    • js/yield/jsx.js

  • Embedded language formatting inside template literals

    • js/multiparser-comments/
    • js/multiparser-css/
    • js/multiparser-graphql/
    • js/multiparser-html/
    • js/multiparser-invalid/
    • js/multiparser-markdown/
    • js/multiparser-text/
    • js/template-literals/css-prop.js
    • js/template-literals/styled-components-with-expressions.js
    • js/template-literals/styled-jsx-with-expressions.js
    • js/template-literals/styled-jsx.js
    • js/range/issue-7082.js
    • js/last-argument-expansion/embed.js
    • js/last-argument-expansion/embed.js

  • Non-standard and experimental syntaxes

    • js/v8_intrinsic
    • js/babel-plugins/
    • js/async-do-expressions/
    • js/do/
    • export X from "mod"
      • js/export-default/export-default-from/
      • js/export-default/escaped/default-escaped.js
      • module <id> {}
        • js/module-blocks
        • js/explicit-resource-management/valid-module-block-top-level-await-using-binding.js
        • js/explicit-resource-management/valid-module-block-top-level-using-binding.js
      • #[] and #{}
        • js/tuple
        • js/record
        • js/arrays/tuple-and-record.js
        • js/arrows/tuple-and-record.js
        • js/binary-expressions/tuple-and-record.js
        • js/class-extends/tuple-and-record.js
        • js/comments-closure-typecast/tuple-and-record.js
        • js/comments/tuple-and-record.js
        • js/function-single-destructuring/tuple-and-record.js
        • js/method-chain/tuple-and-record.js
      • pipeline operator |>
        • js/comments-pipeline-own-line
        • js/partial-application
        • js/pipeline-operator
      • bind operator ::
        • js/arrows-bind/
        • js/bind-expressions/
        • js/objects/expression.js
        • js/no-semi-babylon-extensions/no-semi.js
      • js/destructuring-private-fields/
        • js/deferred-import-evaluation/
        • js/source-phase-imports/
        • js/import-reflection/

In addition to these ignored tests cases, report-es215 also ignores the following test cases:

  • Widespread experimental syntaxes

    • Decorators
      • js/decorators
      • js/decorator-auto-accessors/
      • js/decorators-export/
      • js/ignore/class-expression-decorator.js
      • js/ignore/decorator.js
    • js/import-assertions/
    • js/import-attributes/
    • js/explicit-resource-management

  • Standard ES2016+ syntaxes

    • exponentiation operator **
      • js/async/exponentiation.js
      • js/binary-expressions/exp.js
    • async function and async () => and await
      • js/async/
      • js/arrows/newline-before-arrow/newline-before-arrow.js
      • js/assignment/discussion-15196.js
      • js/assignment/issue-5610.js
      • js/assignment/issue-7091.js
      • js/assignment/issue-10218.js
      • js/assignment/lone-arg.js
      • js/ignore/issue-14404.js
    • Trailing comma in function call
      • js/trailing-comma/function-calls.js
      • js/arrows/arrow-chain-with-trailing-comments.js
    • Object spread and rest { ...x }
      • js/spread
      • js/destructuring/
      • js/destructuring-ignore/
      • js/assignment/destructuring-heuristic.js
      • js/assignment/destructuring.js
      • js/function-single-destructuring/object.js
      • js/last-argument-expansion/assignment-pattern.js
      • js/last-argument-expansion/issue-10708.js
      • js/last-argument-expansion/issue-7518.js
    • async iterator for await
      • js/for-await/
    • Private class field #field
      • js/classes-private-fields
      • js/no-semi/private-field.js
    • try {} catch {}
      • js/optional-catch-binding
    • Nullish coalescing a ?? b
      • js/nullish-coalescing
      • js/arrows/chain-in-logical-expression.js
    • Optional chaining prop?.
      • js/optional-chaining/
      • js/optional-chaining-assignment/
      • js/chain-expression/test.js
    • Bigint
      • js/big-int/
      • js/objects/bigint-key.js
    • Numeric separator 1_000
      • js/literal-numeric-separator/
      • js/quote-props/numeric-separator.js
    • Logical assignment??=, &&=, ...
      • js/logical-assignment/
    • Private brand check #field in
      • js/private-in
    • Private methods
      • js/classes/keyword-property/private.js
      • js/decorator-auto-accessors/private.js
      • js/decorator-auto-accessors/static-private.js
    • class instance fields
      • js/classes/class-fields-features.js
    • Static class blocks static {}
      • js/class-static-block/
    • Top-level await
      • js/top-level-await/
    • regex d flag /regex/d
      • js/regex/d-flag.js",
    • Shebang #!/usr/bin/node
      • js/shebang/
    • regex v flag /regex/v
      • js/regex/v-flag.js

Non-strict test cases

The following test cases are handled in non-strict JavaScript mode, also known as sloppy mode or script mode.

  • js/with/
  • js/sloppy-mode/
  • js/identifier/

Unstable test cases

When formatted twice using Prettier, some tests cases are formatted differently. The Biome testing infrastructure catches this kind of issues.

We decided to match the stabilized formatted version (i.e. the one obtained after multiple run of Prettier on the input - actually a second run is enough to stabilize the output).

The following test cases are affected by this formatting issue:

  • js/sequence-expression/parenthesized.js
  • js/comments/tagged-template-literal.js
  • js/comments/return-statement.js
  • js/last-argument-expansion/embed.js
  • js/for/continue-and-break-comment-without-blocks.js
  • js/class-comment/misc.js
  • js/range/boundary.js
  • js/range/class-declaration.js
  • js/range/multiple-statements2.js

Deliberate formatting divergences

Some divergences are deliberate, because of the strictness of Biome parsing phase or because we think it is more readable to keep the way it is. You can find a detailed description of these test cases in the dedicated issue.

Option support

We implemented all JavaScript options provided by Prettier.

See the documentation of the global configuration for formatter and the specific configuration for the JavaScript formatter.

In contrast to Prettier, Biome only provides as-needed and preserve values for quoteProps. It doesn't provide the consistent value. This is a deliberate choice.