Transformer Reference

Quick reference for all available transformers.

Summary table

Alias table

Detailed reference

trim

|trim

Removes leading and trailing whitespace (spaces, tabs, newlines).

Arguments: none

Example:

trimStart

|trimStart

Removes leading whitespace only.

Arguments: none

trimEnd

|trimEnd

Removes trailing whitespace only.

Arguments: none

indent

|indent:"  "
|indent:"  ":true
|indent

Prepends the given string to each line. By default, empty lines are left empty. Pass true as a second argument to also indent empty lines.

Arguments: 0-2 (string, optional boolean)

• First argument: the indent string (defaults to empty string)
• Second argument: true to include empty lines, false or omitted to skip them

Example:

Input:

line 1

line 3

With |indent:" " (default — skips empty lines):

  line 1

  line 3

With |indent:" ":true, every line gets the indent — including empty lines (which become lines containing only the indent string).

prefix

|prefix:"# "
|prefix

Prepends the string to the entire content (once, not per-line).

Arguments: 0-1 string

suffix

|suffix:"\n"
|suffix

Appends the string to the entire content.

Arguments: 0-1 string

linePrefix

|linePrefix:"// "
|linePrefix:"//! ":true
|line_prefix:"// "

Prepends the string to each line. By default, empty lines are left empty. Pass true as a second argument to also prefix empty lines — essential for code comment blocks.

Arguments: 0-2 (string, optional boolean)

• First argument: the prefix string (defaults to empty string)
• Second argument: true to include empty lines, false or omitted to skip them

Example:

Input:

A fast HTTP client.

Supports async and blocking modes.

With |linePrefix:"/// ":true:

/// A fast HTTP client.
///
/// Supports async and blocking modes.

Without true, the empty line would be left blank (breaking Rust doc comments).

lineSuffix

|lineSuffix:" \\"
|lineSuffix:";":true
|line_suffix:" \\"

Appends the string to each line. By default, empty lines are left empty. Pass true as a second argument to also suffix empty lines.

Arguments: 0-2 (string, optional boolean)

• First argument: the suffix string (defaults to empty string)
• Second argument: true to include empty lines, false or omitted to skip them

wrap

|wrap:"**"

Wraps the entire content: prepends and appends the same string.

Arguments: 0-1 string

Example:

code

|code

Wraps the content in inline code backticks.

Arguments: none

Example:

codeBlock

|codeBlock:"rust"
|codeBlock
|code_block:"typescript"

Wraps the content in a fenced code block. The optional argument specifies the language.

Arguments: 0-1 string (language identifier)

Example with language:

Input: let x = 1;

Output:

```rust
let x = 1;
```

replace

|replace:"search":"replacement"

Replaces all occurrences of the search string with the replacement.

Arguments: exactly 2 strings (search, replacement)

Example:

To delete occurrences, use an empty replacement:

|replace:"unwanted":""

Argument validation

mdt validates transformer arguments at runtime:

Passing the wrong number of arguments produces an error:

error: transformer `replace` expects 2 argument(s), got 1