Introduction
What?
This Prettier plugin (namely prettier-plugin-embed
) provides a configurable solution for formatting embedded languages in the form of template literals within JavaScript or TypeScript files.
Why?
Although Prettier has introduced the embedded-language-formatting
option for formatting embedded languages, it only supports two modes: auto
and off
. Therefore it doesn't allow for individual formatting adjustments for specific languages, nor does it support customizing the languages that require formatting and identifiers for identification. These limitations restrict the usability of this feature. For more detailed discussions, refer to: https://github.com/prettier/prettier/issues/4424 and https://github.com/prettier/prettier/issues/5588.
How?
By leveraging Prettier's plugin system, this plugin overrides the default embed
function of the estree
printer, so varieties of new languages can be hooked in through this function. Check this file to get an idea of how this is accomplished.
Features
-
Support for Additional Languages: Extend the embedded language formatting capability to include languages such as XML, SQL, PHP, and more.
-
Dual Identification Modes: Identify embedded languages by tags identifier`...`
or comments /* identifier */ `...`
preceding the template literals.
-
Customizable Language Identifiers: Customize the identifiers used for identifying the embedded languages.
-
Formatting Opt-out Mechanism: Offer the capability to deactivate formatting for certain identifiers, including the default ones (html
, css
...) supported by the embedded-language-formatting
option.
-
Configurable Formatting Style: Provide additional options to tailor the formatting style for embedded languages.
-
Strongly Typed API: Benefit from comprehensive type support for configuring this plugin's options when employing the Prettier API in TypeScript.
-
Easy Integration: Integrate with the existing Prettier setup seamlessly, requiring minimal configuration to get started.
Installation
npm i -D prettier-plugin-embed
Usage
Getting Started
This is a Prettier plugin, which follows the standard usage pattern of many other Prettier plugins:
Via --plugin
:
prettier --write main.ts --plugin=prettier-plugin-embed
Via the plugins
options:
await prettier.format(code, {
filepath: "main.ts",
plugins: ["prettier-plugin-embed"],
});
{
"plugins": ["prettier-plugin-embed"]
}
Quick Start Config Examples
Here're some quick start config examples to use this plugin for various embedded languages. Check beblow for a detailed explanation of all the available options.
An Overview of the Philosophy
To use this plugin, embedded-language-formatting
option must be set to auto
(which is the default setting as of now), because this option serves as the main switch for activating embedded language formatting.
This plugin does not aim to implement parsers or printers to support every newly added embedded language. Instead, ideally, it makes use of existing Prettier plugins for those languages and only adds formatting support when they are embedded in template literals.
Therefore, to enable formatting for a specific embedded language, the corresponding Prettier plugin for that language must also be loaded. For example, if you wish to format embedded XML language, you will need to load both this plugin and @prettier/plugin-xml
. To find out which other plugins are required when using this plugin, please refer to the Language-Specific Options section below.
Embedded languages to be formatted are required to be enclosed in the template literals, and are identified by the preceding tags identifier`...`
or block comments /* identifier */ `...`
. This plugin comes pre-configured with a built-in set of identifiers for identifying various embedded languages. For instance, using identifiers like xml
or svg
will trigger automatic formatting for the embedded XML language. You can specify an alternative list of identifiers using the embeddedXmlIdentifiers
option. The naming convention for these options follows the pattern of embedded<Language>Identifiers
for other languages as well. Further details on these options and how to configure them are also available in the Language-Specific Options section.
To exclude certain identifiers from being identified, including the default ones supported by the embedded-language-formatting
option, add them to the list of the embeddedNoopIdentifiers
option. Any matching identifiers listed in this option will take precedence over other embedded<Language>Identifiers
options, effectively disabling their formatting.
[!IMPORTANT]
Until this notice is removed, always specify identifiers explicitly and do not rely on the built-in defaults, as they may be subject to change.
Language-Specific Options
Supported embedded languages are:
Click Here to Toggle
NOOP
embeddedNoopIdentifiers
- Type:
string[]
- Default:
[]
- Description: Tag or comment identifiers that prevent their subsequent template literals from being identified as embedded languages and thus from being formatted.
This "language" doesn't require other plugins and can override the native embedded language formatting. It serves as a way to turn off embedded language formatting for the specified language identifiers.
CSS
embeddedCssIdentifiers
- Type:
string[]
- Default:
["css"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded CSS language.
embeddedCssParser
Formatting embedded CSS language doesn't require other plugins and uses the parsers and printers provided by Prettier natively.
This can override the native formatting bahavior for embedded CSS language. If you want to keep the native behavior, set embeddedCssIdentifiers
to []
or other identifiers.
If you want to specify different parsers for different identifiers, check embeddedOverrides
.
ES (ECMAScript/JavaScript)
embeddedEsIdentifiers
embeddedEsParser
Formatting embedded ECMAScript/JavaScript language doesn't require other plugins and uses the parsers and printers provided by Prettier natively.
If you want to specify different parsers for different identifiers, check embeddedOverrides
.
GLSL
embeddedGlslIdentifiers
- Type:
string[]
- Default:
["glsl", "shader"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded GLSL language. This option requires the
prettier-plugin-glsl
plugin.
Formatting embedded GLSL language requires the prettier-plugin-glsl
plugin to be loaded as well.
GraphQL
embeddedGraphqlIdentifiers
- Type:
string[]
- Default:
["graphql", "gql"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded GraphQL language.
Formatting embedded GraphQL language doesn't require other plugins and uses the parsers and printers provided by Prettier natively.
This can override the native formatting behavior for embedded GraphQL language. If you want to keep the native behavior, set embeddedGraphqlIdentifiers
to []
or other identifiers.
HTML
embeddedHtmlIdentifiers
- Type:
string[]
- Default:
["html", "xhtml"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded HTML language.
embeddedHtmlParser
Formatting embedded HTML language doesn't require other plugins and uses the parsers and printers provided by Prettier natively.
This can override the native formatting behavior for embedded HTML language. If you want to keep the native behavior, set embeddedHtmlIdentifiers
to []
or other identifiers.
If you want to specify different parsers for different identifiers, check embeddedOverrides
.
INI
embeddedIniIdentifiers
- Type:
string[]
- Default:
["ini", "cfg", "pro"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded INI language. This option requires the
prettier-plugin-ini
plugin.
Formatting embedded INI language requires the prettier-plugin-ini
plugin to be loaded as well. And options supported by prettier-plugin-ini
can therefore be used to further control the formatting behavior.
Java
embeddedJavaIdentifiers
- Type:
string[]
- Default:
["java"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded Java language. This option requires the
prettier-plugin-java
plugin.
Formatting embedded Java language requires the prettier-plugin-java
plugin to be loaded as well. And options supported by prettier-plugin-java
can therefore be used to further control the formatting behavior.
JSON
embeddedJsonIdentifiers
- Type:
string[]
- Default:
["json", "jsonl"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded JSON language.
embeddedJsonParser
Formatting embedded JSON language doesn't require other plugins and uses the parsers and printers provided by Prettier natively.
If you want to specify different parsers for different identifiers, check embeddedOverrides
.
JSONata
embeddedJsonataIdentifiers
- Type:
string[]
- Default:
["jsonata"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded JSONata language. This option requires the
@stedi/prettier-plugin-jsonata
plugin.
Formatting embedded JSONata language requires the @stedi/prettier-plugin-jsonata
plugin to be loaded as well.
LaTeX
embeddedLatexIdentifiers
Formatting embedded LaTeX language requires the prettier-plugin-latex
plugin to be loaded as well.
Markdown
embeddedMarkdownIdentifiers
- Type:
string[]
- Default:
["md", "markdown"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded Markdown language.
embeddedMarkdownParser
Formatting embedded Markdown language doesn't require other plugins and uses the parsers and printers provided by Prettier natively.
This can override the native formatting for embedded Markdown language. If you want to keep the native behavior, set embeddedMarkdownIdentifiers
to []
or other identifiers.
If you want to specify different parsers for different identifiers, check embeddedOverrides
.
The remark
parser is an alias of the markdown
parser.
NGINX
embeddedNginxIdentifiers
- Type:
string[]
- Default:
["nginx"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded NGINX language. This option requires the
prettier-plugin-nginx
plugin.
Formatting embedded NGINX language requires the prettier-plugin-nginx
plugin to be loaded as well. And options supported by prettier-plugin-nginx
can therefore be used to further control the formatting behavior.
Pegjs
embeddedPegjsIdentifiers
- Type:
string[]
- Default:
["pegjs", "peggy", "peg"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded Pegjs language. This option requires the
prettier-plugin-pegjs
plugin.
Formatting embedded Pegjs language requires the prettier-plugin-pegjs
plugin to be loaded as well. And options supported by prettier-plugin-pegjs
can therefore be used to further control the formatting behavior.
Note that prettier-plugin-pegjs
supports different parsers for the action blocks and they are specified by the actionParser
option. If you want to specify different action parsers for different identifiers, check embeddedOverrides
.
PHP
embeddedPhpIdentifiers
- Type:
string[]
- Default:
["php", "php5"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded PHP language. This option requires the
@prettier/plugin-php
plugin.
Formatting embedded PHP language requires the @prettier/plugin-php
plugin to be loaded as well. And options supported by @prettier/plugin-php
can therefore be used to further control the formatting behavior.
Prisma
embeddedPrismaIdentifiers
- Type:
string[]
- Default:
["prisma"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded Prisma language. This option requires the
prettier-plugin-prisma
plugin.
Formatting embedded Prisma language requires the prettier-plugin-prisma
plugin to be loaded as well.
Properties
embeddedPropertiesIdentifiers
- Type:
string[]
- Default:
["properties"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded Properties language. This option requires the
prettier-plugin-properties
plugin.
Formatting embedded Properties language requires the prettier-plugin-properties
plugin to be loaded as well. And options supported by prettier-plugin-properties
can therefore be used to further control the formatting behavior.
Pug
embeddedPugIdentifiers
- Type:
string[]
- Default:
["pug", "jade"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded Pug language. This option requires the
@prettier/plugin-pug
plugin.
Formatting embedded Pug language requires the @prettier/plugin-pug
plugin to be loaded as well. And options supported by @prettier/plugin-pug
can therefore be used to further control the formatting behavior.
Ruby
embeddedRubyIdentifiers
- Type:
string[]
- Default:
["ruby"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded Ruby language. This option requires the
@prettier/plugin-ruby
plugin.
embeddedRubyParser
- Type:
"ruby" | "rbs" | "haml"
- Default:
"ruby"
- Description: The parser used to parse the embedded Ruby language. This option requires the
@prettier/plugin-ruby
plugin.
Formatting embedded Ruby language requires the @prettier/plugin-ruby
to be loaded and its dependencies to be installed as well. And options supported by @prettier/plugin-ruby
can therefore be used to further control the formatting behavior.
If you want to specify different parsers for different identifiers, check embeddedOverrides
.
Sh (Shell)
embeddedShIdentifiers
- Type:
string[]
- Default:
["sh"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded Shell language. This option requires the
prettier-plugin-sh
plugin.
Formatting embedded Shell language requires the prettier-plugin-sh
plugin to be loaded as well. And options supported by prettier-plugin-sh
can therefore be used to further control the formatting behavior.
Note that prettier-plugin-sh
supports different variants of shell syntaxes and they are specified by the variant
option. If you want to specify different variants for different identifiers, check embeddedOverrides
.
SQL
embeddedSqlIdentifiers
- Type:
string[]
- Default:
["sql"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded SQL language. This option requires the
prettier-plugin-sql
plugin or the prettier-plugin-sql-cst
plugin.
embeddedSqlPlugin
embeddedSqlParser
Formatting embedded SQL language requires the prettier-plugin-sql
plugin or the prettier-plugin-sql-cst
plugin to be loaded as well. And options supported by prettier-plugin-sql
, or options supported by prettier-plugin-sql-cst
can therefore be used to further control the formatting behavior.
Note that prettier-plugin-sql
supports many different SQL dialects which are specified by the language
, database
or dialect
option. And prettier-plugin-sql-cst
also supports various parsers as shown above. If you want to specify different dialects or parsers for different identifiers, check embeddedOverrides
.
TOML
embeddedTomlIdentifiers
- Type:
string[]
- Default:
["toml"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded TOML language. This option requires the
prettier-plugin-toml
plugin.
Formatting embedded TOML language requires the prettier-plugin-toml
plugin to be loaded as well. And options supported by prettier-plugin-toml
can therefore be used to further control the formatting behavior.
TS (TypeScript)
embeddedTsIdentifiers
embeddedTsParser
Formatting embedded TypeScript language doesn't require other plugins and uses the parsers and printers provided by Prettier natively.
If you want to specify different parsers for different identifiers, check embeddedOverrides
.
XML
embeddedXmlIdentifiers
- Type:
string[]
- Default:
["xml", "opml", "rss", "svg"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded XML language. This option requires the
@prettier/plugin-xml
plugin.
Formatting embedded XML language requires the @prettier/plugin-xml
plugin to be loaded as well. And options supported by @prettier/plugin-xml
can therefore be used to further control the formatting behavior.
YAML
embeddedYamlIdentifiers
- Type:
string[]
- Default:
["yaml", "yml"]
- Description: Tag or comment identifiers that make their subsequent template literals be identified as embedded YAML language.
Formatting embedded YAML language doesn't require other plugins and uses the parsers and printers provided by Prettier natively.
Language-Agnostic Options
Language-Agnostic
- Type:
string[]
- Default:
[]
- Description: Turns off
/* identifier */ `...`
comment-based embedded language identification for the specified identifiers.
noEmbeddedIdentificationByTag
- Type:
string[]
- Default:
[]
- Description: Turns off
identifier`...`
tag-based embedded language identification for the specified identifiers.
preserveEmbeddedExteriorWhitespaces
- Type:
string[]
- Default:
[]
- Description: Preserves leading and trailing whitespaces in the formatting results for the specified identifiers.
noEmbeddedMultiLineIndentation
- Type:
string[]
- Default:
[]
- Description: Turns off auto indentation in the formatting results when they are formatted to span multi lines for the specified identifiers.
embeddedOverrides
- Type:
string
- Default:
undefined
- Description: Option overrides for the specified identifiers. It should either be a stringified JSON or an absolute filepath to the option overrides file. See below for a detailed explanation.
embeddedOverrides
This option is provided for users to override certain options based on identifiers. Due to the lack of support for using objects in prettier plugin options (https://github.com/prettier/prettier/issues/14671), it accepts a stringified json string, or a file path with an extension of .json
, .jsonc
, .js
, .cjs
, .mjs
, .ts
, .cts
or .mts
as its value. If no extension is provided, it will be treated as a .json
/.jsonc
file. For relative paths, it will automatically figure out the prettier config location and use that as the base path.
[!NOTE]
The support for using .ts
, .mts
or .cts
files for embeddedOverrides
requires a minimal node
version of 18.19.0, and tsx
as a dependency in your project. And it currently doesn't work with the Prettier VSCode extension.
The resolved value should be an array of objects. Each object in the array must have 2 fields: identifiers
and options
. The options
are considerred overrides that will be applied to the global options
of prettier for those idenfitiers
only. It's like the overrides
of prettier
, but it is identifier-based instead of file-based.
In a json file, the root is the array of objects. In a JavaScript file, the array of objects should be a default export, or a named export with the name embeddedOverrides
.
An example .json
/.jsonc
file is:
[
{
"identifiers": ["sql"],
"options": {
"keywordCase": "lower"
}
},
{
"identifiers": ["mysql"],
"options": {
"keywordCase": "upper"
}
}
]
[!CAUTION]
Please note that not every option is supported to override. That largely depends on at which phase those options will kick in and take effect. For example, you can't override tabWidth
in embeddedOverrides
because this option is used in the printDocToString
phase, where prettier-plugin-embed
cannot override this option for only a set of specified identifiers. To find the list of unsupported options, please check the interface definition of EmbeddedOverride
in the source code.
Typed Options
There're several ways to use the typed options provided by this plugin. Taking the embedded SQL language as an example:
-
Augment the Options
type from Prettier
to use plugin-specific options
Register options from prettier-plugin-embed
(this plugin):
Register options from prettier-plugin-sql
:
Other embedded languages share the same pattern:
-
Import plugin-specific options
Import options from prettier-plugin-embed
(this plugin):
import type { PluginEmbedOptions } from "prettier-plugin-embed";
Import options from prettier-plugin-sql
:
import type { PluginSqlOptions } from "prettier-plugin-embed/embedded/sql/plugin-sql-types";
NOTE: You can also import the types from the prettier-plugin-sql
plugin directly. However, not all of the plugins provide types, or provide them in a predictable way, so this plugin exports them in a more unified manner.
Other embedded languages share the same pattern:
import type { Plugin<Language>Options } from "prettier-plugin-embed/embedded/<language>/<(no prettier or scope) plugin name>-types";
-
Use JSDoc
in JavaScript files
const pluginEmbedOptions = {
embeddedSqlIdentifiers: ["sql"],
};
const pluginSqlOptions = {
language: "postgresql",
keywordCase: "upper",
};
Contributing
Bug fixes, new language support and tests are welcome. Please have a look at the project structure before getting started. Feel free to leave questions or suggestions.
License
MIT