Struct MagicString 

pub struct MagicString<'s> { /* private fields */ }

Implementations

impl<'text> MagicString<'text>

pub fn append(&mut self, source: impl Into<Cow<'text, str>>) -> &mut Self

pub fn append_left( &mut self, text_index: u32, content: impl Into<Cow<'text, str>>, ) -> Result<&mut Self, String>

Errors

Returns Err if text_index falls inside a chunk that has already been edited, since the chunk cannot be split there.

Example

 use string_wizard::MagicString;
 let mut s = MagicString::new("01234");
 s.append_left(2, "a").unwrap();
 s.append_left(2, "b").unwrap();
 assert_eq!(s.to_string(), "01ab234")

pub fn append_right( &mut self, text_index: u32, content: impl Into<Cow<'text, str>>, ) -> Result<&mut Self, String>

Errors

Returns Err if text_index falls inside a chunk that has already been edited, since the chunk cannot be split there.

Example

use string_wizard::MagicString;
let mut s = MagicString::new("01234");
s.append_right(2, "A").unwrap();
s.append_right(2, "B").unwrap();
s.append_left(2, "a").unwrap();
s.append_left(2, "b").unwrap();
assert_eq!(s.to_string(), "01abAB234")

impl MagicString<'_>

pub fn get_indent_string(&self) -> &str

pub fn indent(&mut self) -> Result<&mut Self, String>

Errors

Propagates the split error from Self::prepend_right. Indentation only splits chunks that have not been edited, so this is not reachable in practice.

pub fn indent_with( &mut self, opts: IndentOptions<'_, '_>, ) -> Result<&mut Self, String>

Errors

See Self::indent.

impl MagicString<'_>

pub fn remove(&mut self, start: u32, end: u32) -> Result<&mut Self, String>

Removes characters in the range [start, end) from the generated output.

Unlike update/overwrite, this iterates by original position (via chunk_by_start) rather than by linked-list order, so it works correctly across moved content.

pub fn relocate( &mut self, start: u32, end: u32, to: u32, ) -> Result<&mut Self, String>

Moves the characters from start and end to index. Returns this.

pub fn snip(&self, start: u32, end: u32) -> Result<Self, String>

Returns a clone with content outside the specified range removed. This is equivalent to clone().remove(0, start).remove(end, original.len()).

impl<'text> MagicString<'text>

pub fn prepend(&mut self, source: impl Into<Cow<'text, str>>) -> &mut Self

pub fn prepend_left( &mut self, text_index: u32, content: impl Into<Cow<'text, str>>, ) -> Result<&mut Self, String>

Errors

Returns Err if text_index falls inside a chunk that has already been edited, since the chunk cannot be split there.

pub fn prepend_right( &mut self, text_index: u32, content: impl Into<Cow<'text, str>>, ) -> Result<&mut Self, String>

Errors

Returns Err if text_index falls inside a chunk that has already been edited, since the chunk cannot be split there.

impl<'text> MagicString<'text>

pub fn replace( &mut self, from: &str, to: impl Into<Cow<'text, str>>, ) -> Result<&mut Self, String>

pub fn replace_all( &mut self, from: &str, to: impl Into<Cow<'text, str>>, ) -> Result<&mut Self, String>

pub fn replace_with( &mut self, from: &str, to: impl Into<Cow<'text, str>>, options: ReplaceOptions, ) -> Result<&mut Self, String>

impl<'text> MagicString<'text>

pub fn reset(&mut self, start: u32, end: u32) -> Result<&mut Self, String>

Resets the portion of the string from start to end to its original content. This undoes any modifications (updates, overwrites, intro/outro additions) made to that range.

Errors

• If start is greater than to end
• If the range is out of bounds

impl<'text> MagicString<'text>

pub fn slice(&self, start: u32, end: Option<u32>) -> Result<String, String>

Returns the content of the generated string that corresponds to the original positions from start to end.

If end is None, it defaults to the original string length.

impl MagicString<'_>

pub fn source_map(&self, opts: SourceMapOptions) -> SourceMap<'static>

impl<'text> MagicString<'text>

pub fn trim(&mut self, char_type: Option<&str>) -> &mut Self

Trims whitespace from the start and end of the string.

pub fn trim_start(&mut self, char_type: Option<&str>) -> &mut Self

Trims whitespace from the start of the string.

pub fn trim_end(&mut self, char_type: Option<&str>) -> &mut Self

Trims whitespace from the end of the string.

pub fn trim_lines(&mut self) -> &mut Self

Trims newlines from the start and end of the string.

impl<'text> MagicString<'text>

pub fn update( &mut self, start: u32, end: u32, content: impl Into<Cow<'text, str>>, ) -> Result<&mut Self, String>

A shorthand for update_with(start, end, content, Default::default());

pub fn update_with( &mut self, start: u32, end: u32, content: impl Into<Cow<'text, str>>, opts: UpdateOptions, ) -> Result<&mut Self, String>

impl<'text> MagicString<'text>

pub fn new(source: impl Into<Cow<'text, str>>) -> Self

pub fn with_options( source: impl Into<Cow<'text, str>>, options: MagicStringOptions, ) -> Self

pub fn source(&self) -> &str

pub fn filename(&self) -> Option<&str>

pub fn ignore_list(&self) -> bool

pub fn len(&self) -> usize

Returns the length in UTF-8 bytes of the content within chunks (intro + content + outro per chunk), excluding the global intro/outro from prepend/append. This aligns with the reference magic-string behavior.

Note this counts bytes. Callers that need the length JavaScript would report (UTF-16 code units, as the reference magic-string returns) must use Self::len_utf16.

pub fn len_utf16(&self) -> usize

Returns the length in UTF-16 code units of the content within chunks, excluding the global intro/outro — the same range Self::len covers.

This is what the reference magic-string length() returns, since JavaScript string length is measured in UTF-16 code units.

pub fn is_empty(&self) -> bool

Returns true if all chunk content (intro + content + outro) is whitespace or empty. This aligns with the reference magic-string behavior where isEmpty() uses .trim().

pub fn has_changed(&self) -> bool

Indicates if the string has been changed.

The length check is only a fast path for “definitely changed”, so it has to measure the same span as the string comparison below it: the whole output, global intro/outro included. Comparing against Self::len instead would report a change for edits that cancel out, e.g. remove(0, 1) followed by prepend("a").

pub fn last_char(&self) -> Option<char>

Returns the last character of the generated string, or None if empty.

pub fn last_line(&self) -> String

Returns the content after the last newline in the generated string.

pub fn prepend_outro(&mut self, content: impl Into<Cow<'text, str>>)

pub fn append_intro(&mut self, content: impl Into<Cow<'text, str>>)

pub fn is_range_within_edited_chunk(&self, start: u32, end: u32) -> bool

Returns true if the byte range [start, end) lies within a single chunk that has already been edited. Callers use this for split points that cannot be expressed as a byte index (a UTF-16 position inside a surrogate pair): the split would land strictly inside the character spanning [start, end), so it hits an edited chunk exactly when this returns true.

Trait Implementations

impl<'s> Clone for MagicString<'s>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'s> Debug for MagicString<'s>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for MagicString<'_>

fn default() -> Self

Returns the “default value” for a type.

impl ToString for MagicString<'_>

fn to_string(&self) -> String

Converts the given value to a String.