stable

Prettier 3.2: Support JSONC and Angular’s ICU expression

January 12, 2024

Sosuke Suzuki (@sosukesuzuki)

This release includes new features such as adding a JSONC parser, adding Angular’s ICU expressions, and many bug fixes.

We are still seeking feedback for the --experimental-ternaries option released in Prettier 3.1. Please read A curious case of the ternaries and respond via the Google Forms link provided.

Additionally, we recommend reading Prettier's CLI: A Performance Deep Dive by Fabio Spampinato. This faster CLI is slated to be released as version 4.0.

If you appreciate Prettier and would like to support our work, please consider sponsoring us directly via our OpenCollective or by sponsoring the projects we depend on, such as typescript-eslint, remark, and Babel. Thank you for your continued support!

Highlights

JSON

New jsonc parser added (#15831 by @fisker)

Previously, we infer the parser of .jsonc files to be json, but if we want keep the trailing comma, we'll have to use a hacky workaround config {parser: "json5", quoteProps: "preserve", singleQuote: false}.

The new added jsonc parser:

  • Always quote the object keys.
  • Wrap strings with double quotes.
  • Of course, respect the trailingComma option.

Angular

Support formatting for Angular ICU expression (#15777 by @sosukesuzuki)

Support two kinds of Angular ICU expressions: plural and select.

<span i18n>
  Updated:
  {minutes, plural,
    =0 {just now}
    =1 {one minute ago}
    other {{{minutes}} minutes ago}
  }
</span>

<span i18n>
  The author is {gender, select, male {male} female {female} other {other}}
</span>

Other Changes

JavaScript

Avoid introducing linebreaks in template interpolations (#15209 by @bakkot)

In a template string like

`this is a long message which contains an interpolation: ${format(data)} <- like this`;

avoid adding a linebreak when formatting the expression unless one is already present or it's unavoidable due to e.g. a nested function. Previously a linebreak could be introduced whenever some interpolation in the template was sufficiently "not simple":

`this is a long message which contains an interpolation: ${format(
  data,
)} <- like this`;

Now it will instead be left alone.

If a linebreak is already present within the ${...}, format as normal.

Fix non-idempotent formatting of method chain with empty line (#15522 by @seiyab)

// Input
Foo.a()

.b();

// Prettier 3.1 (first format)
Foo.a()
.b();

// Prettier 3.1 (second format)
Foo.a().b();


// Prettier 3.2
Foo.a()

  .b();

Fix formatting of ternary in function call (#15677 by @fisker)

// Input
stopDirectory = await (useCache
  ? memoizedFindProjectRoot
  : findProjectRootWithoutCache)(path.dirname(path.resolve(filePath)));

// Prettier 3.1
stopDirectory = await (useCache
  ? memoizedFindProjectRoot
  : findProjectRootWithoutCache)(path.dirname(path.resolve(filePath)));

// Prettier 3.2
stopDirectory = await (
  useCache ? memoizedFindProjectRoot : findProjectRootWithoutCache
)(path.dirname(path.resolve(filePath)));

Fix inconsistencies for optional-chaining (#15806 by @fisker)

Only happens when using typescript, meriyah or other ESTree parsers except babel.

// Input
function someFunctionName() {
  return isEqual(a.map(([t, _]) => t?.id), b.map(([t, _]) => t?.id));
  return isEqual(a?.map(([t, _]) => t?.id), b?.map(([t, _]) => t?.id));
}
theValue = Object.entries(someLongObjectName).filter(
  ([listingId]) => someListToCompareToHere.includes(listingId),
);
theValue = Object.entries(someLongObjectName).filter(
  ([listingId]) => someListToCompareToHere?.includes(listingId),
);

// Prettier 3.1
function someFunctionName() {
  return isEqual(
    a.map(([t, _]) => t?.id),
    b.map(([t, _]) => t?.id),
  );
  return isEqual(a?.map(([t, _]) => t?.id), b?.map(([t, _]) => t?.id));
}
theValue = Object.entries(someLongObjectName).filter(([listingId]) =>
  someListToCompareToHere.includes(listingId),
);
theValue = Object.entries(someLongObjectName).filter(
  ([listingId]) => someListToCompareToHere?.includes(listingId),
);

// Prettier 3.2
function someFunctionName() {
  return isEqual(
    a.map(([t, _]) => t?.id),
    b.map(([t, _]) => t?.id),
  );
  return isEqual(
    a?.map(([t, _]) => t?.id),
    b?.map(([t, _]) => t?.id),
  );
}
theValue = Object.entries(someLongObjectName).filter(([listingId]) =>
  someListToCompareToHere.includes(listingId),
);
theValue = Object.entries(someLongObjectName).filter(([listingId]) =>
  someListToCompareToHere?.includes(listingId),
);

Fix comments in if (#15826 by @fisker)

// Input
if (foo) for (i = 2; i > 0; i--) console.log(i); // comment 1
else bar();

for (;;){
  if (foo) continue; // comment 2
  else bar();
}

// Prettier 3.1
Error: Comment "comment 2" was not printed. Please report this error!

// Prettier 3.2
if (foo)
  for (i = 2; i > 0; i--) console.log(i); // comment 1
else bar();

for (;;) {
  if (foo)
    continue; // comment 2
  else bar();
}

TypeScript

Improve conditional type alias layout (#15811 by @seiyab)

// Input
type FallbackFlags<F extends Flags | undefined> =
  Equals<NonNullableFlag<F>["flags"], {}> extends true
    ? Dict<any>
    : NonNullableFlag<F>["flags"];

// Prettier 3.1
type FallbackFlags<F extends Flags | undefined> = Equals<
  NonNullableFlag<F>["flags"],
  {}
> extends true
  ? Dict<any>
  : NonNullableFlag<F>["flags"];

// Prettier 3.2
type FallbackFlags<F extends Flags | undefined> =
  Equals<NonNullableFlag<F>["flags"], {}> extends true
    ? Dict<any>
    : NonNullableFlag<F>["flags"];

HTML

Fix formatting of prettier-ignored unclosed elements (#15748 by @fisker)

<!-- Input -->
<!-- prettier-ignore -->
<h1>
Hello <span>world!

<!-- Prettier 3.1 -->
<!-- prettier-ignore -->
<h1>

<!-- Prettier 3.2 -->
<!-- prettier-ignore -->
<h1>
Hello <span>world!

Angular

Fix prettier-ignored angular control flow block (#15827 by @fisker)

<!-- Input -->
<!-- prettier-ignore -->
@if (condition) {
  Foo
} @else {
  Other
}

<!-- Prettier 3.1 -->
<!-- prettier-ignore -->
@if (condition) {
  Foo
}
} @else {
  Other
}

<!-- Prettier 3.2 -->
<!-- prettier-ignore -->
@if (condition) {
  Foo
}
@else {
  Other
}

Avoid adding colon for track in 3rd expression of for blocks (#15887 by @sosukesuzuki)

<!-- Input -->
@for (item of items; let i = $index; track block) {}

<!-- Prettier 3.1 -->
@for (item of items; let i = $index; track: block) {}

<!-- Prettier 3.2 -->
@for (item of items; let i = $index; track block) {}

Ember / Handlebars

Preserve path literal segments (#15605 by @maxpowa)

Fixes scenarios where an input handlebars file containing literal segments would be reformatted to unwrap the literal segments, causing syntax errors in the resulting output.

<!-- Input -->
{{input.[funky<api!response]}}
{{input.[this one has spaces]}}
{{input.[anotherone].[0]}}

<!-- Prettier 3.1 -->
{{input.funky<api!response}}
{{input.this one has spaces}}
{{input.anotherone.0}}

<!-- Prettier 3.2 -->
{{input.[funky<api!response]}}
{{input.[this one has spaces]}}
{{input.anotherone.[0]}}

GraphQL

Improve GraphQL union types formatting (#15870 by @ArchitGajjar)

# Input
union SearchResult = Conference| Festival | Concert | Venue | Conference| Festival | Concert | Venue

# Prettier 3.1
union SearchResult =
    Conference
  | Festival
  | Concert
  | Venue
  | Conference
  | Festival
  | Concert
  | Venue

# Prettier 3.2
union SearchResult =
  | Conference
  | Festival
  | Concert
  | Venue
  | Conference
  | Festival
  | Concert
  | Venue

API

Support absolute path as plugin in config file (#15666 by @fisker)

// prettier.config.cjs
module.exports = {
  plugins: [
    // posix style
    "/path/to/plugin.js",
    // Windows style
    "D:\\\\path\\to\\plugin.js",
    // Use `require.resolve`
    require.resolve("my-awesome-prettier-plugin"),
  ],
};

Fix getFileInfo and getSupportInfo type definitions (#15854 by @auvred)

const plugin: Plugin = {};

prettier.getFileInfo("./file.ext", {
  plugins: [plugin],
});

prettier.getSupportInfo({ plugins: [plugin], showDeprecated: true });

Miscellaneous

Fix false claim in docs that cursorOffset is incompatible with rangeStart/rangeEnd (#15750 by @ExplodingCabbage)

The cursorOffset option has in fact been compatible with rangeStart/rangeEnd for over 5 years, thanks to work by @ds300. However, Prettier's documentation (including the CLI --help text) continued to claim otherwise, falsely. The documentation is now fixed.

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