Code formatter
Deno ships with a built-in code formatter that will auto-format the following files:
File Type | Extension |
---|---|
JavaScript | .js |
TypeScript | .ts |
JSX | .jsx |
TSX | .tsx |
Markdown | .md , .markdown |
JSON | .json |
JSONC | .jsonc |
In addition, deno fmt
can format code snippets in Markdown files. Snippets
must be enclosed in triple backticks and have a language attribute.
# format all supported files in the current directory and subdirectories
deno fmt
# format specific files
deno fmt myfile1.ts myfile2.ts
# format all supported files in specified directory and subdirectories
deno fmt src/
# check if all the supported files in the current directory and subdirectories are formatted
deno fmt --check
# format stdin and write to stdout
cat file.ts | deno fmt -
Ignoring Code
Ignore formatting code by preceding it with a // deno-fmt-ignore
comment in
TS/JS/JSONC:
// deno-fmt-ignore
export const identity = [
1, 0, 0,
0, 1, 0,
0, 0, 1,
];
Or ignore an entire file by adding a // deno-fmt-ignore-file
comment at the
top of the file.
In markdown you may use a <!-- deno-fmt-ignore -->
comment or ignore a whole
file with a <!-- deno-fmt-ignore-file -->
comment. To ignore a section of
markdown, surround the code with <!-- deno-fmt-ignore-start -->
and
<!-- deno-fmt-ignore-end -->
comments.
Configuration
ℹ️ It is recommended to stick with default options.
Starting with Deno v1.14 a formatter can be customized using either a configuration file or following CLI flags:
--options-use-tabs
- Whether to use tabs. Defaults to false (using spaces).--options-line-width
- The width of a line the printer will try to stay under. Note that the printer may exceed this width in certain cases. Defaults to 80.--options-indent-width
- The number of characters for an indent. Defaults to 2.--options-single-quote
- Whether to use single quote. Defaults to false (using double quote).--options-prose-wrap={always,never,preserve}
- Define how prose should be wrapped in Markdown files. Defaults to "always".