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Overview

The EditBuffer class extends EventEmitter and provides a complete text editing solution with cursor management, undo/redo history, and grapheme-aware text operations. It’s designed for building text editors and interactive text input components.

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Constructor

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lib
RenderLib
required
The render library instance.
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ptr
Pointer
required
Pointer to the native buffer.

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Static Methods

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create

Creates a new EditBuffer instance. 
static create(widthMethod: WidthMethod): EditBuffer
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widthMethod
WidthMethod
required
The width calculation method for character rendering.
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return
EditBuffer
A new EditBuffer instance.

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Properties

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id

readonly id: number
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id
number
Unique identifier for this buffer instance.

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ptr

get ptr(): Pointer
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ptr
Pointer
The native pointer to the buffer.

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Text Operations

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setText

Sets text and completely resets the buffer state (clears history). 
setText(text: string): void
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text
string
required
The text content to set.

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setTextOwned

Sets text using owned memory and resets buffer state. Native code takes ownership. 
setTextOwned(text: string): void
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text
string
required
The text content to set.

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replaceText

Replaces text while preserving undo history (creates an undo point). 
replaceText(text: string): void
​
text
string
required
The replacement text content.

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replaceTextOwned

Replaces text using owned memory while preserving undo history. 
replaceTextOwned(text: string): void
​
text
string
required
The replacement text content.

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getText

Retrieves the current text content. 
getText(): string
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return
string
The current text content.

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getTextRange

Retrieves a range of text by character offsets. 
getTextRange(startOffset: number, endOffset: number): string
​
startOffset
number
required
The starting character offset.
​
endOffset
number
required
The ending character offset.
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return
string
The text in the specified range.

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getTextRangeByCoords

Retrieves a range of text by line/column coordinates. 
getTextRangeByCoords(
  startRow: number,
  startCol: number,
  endRow: number,
  endCol: number
): string
​
startRow
number
required
The starting row (0-based).
​
startCol
number
required
The starting column (0-based).
​
endRow
number
required
The ending row (0-based).
​
endCol
number
required
The ending column (0-based).
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return
string
The text in the specified range.

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getLineCount

Gets the number of lines in the buffer. 
getLineCount(): number
​
return
number
The number of lines.

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Editing Operations

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insertChar

Inserts a character at the current cursor position. 
insertChar(char: string): void
​
char
string
required
The character to insert.

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insertText

Inserts text at the current cursor position. 
insertText(text: string): void
​
text
string
required
The text to insert.

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deleteChar

Deletes the character at the cursor position (forward delete). 
deleteChar(): void

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deleteCharBackward

Deletes the character before the cursor position (backspace). 
deleteCharBackward(): void

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deleteRange

Deletes a range of text by coordinates. 
deleteRange(
  startLine: number,
  startCol: number,
  endLine: number,
  endCol: number
): void
​
startLine
number
required
The starting line (0-based).
​
startCol
number
required
The starting column (0-based).
​
endLine
number
required
The ending line (0-based).
​
endCol
number
required
The ending column (0-based).

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newLine

Inserts a new line at the cursor position. 
newLine(): void

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deleteLine

Deletes the current line. 
deleteLine(): void

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Cursor Operations

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getCursorPosition

Gets the current cursor position. 
getCursorPosition(): LogicalCursor
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return
LogicalCursor
Object containing row, col, and offset properties.

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setCursor

Sets the cursor to a specific line and column. 
setCursor(line: number, col: number): void
​
line
number
required
The line number (0-based).
​
col
number
required
The column number (0-based).

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setCursorToLineCol

Sets the cursor to a specific line and column. 
setCursorToLineCol(line: number, col: number): void
​
line
number
required
The line number (0-based).
​
col
number
required
The column number (0-based).

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setCursorByOffset

Sets the cursor by character offset. 
setCursorByOffset(offset: number): void
​
offset
number
required
The character offset (0-based).

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moveCursorLeft

Moves the cursor one grapheme left. 
moveCursorLeft(): void

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moveCursorRight

Moves the cursor one grapheme right. 
moveCursorRight(): void

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moveCursorUp

Moves the cursor one line up. 
moveCursorUp(): void

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moveCursorDown

Moves the cursor one line down. 
moveCursorDown(): void

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gotoLine

Moves the cursor to the start of a specific line. 
gotoLine(line: number): void
​
line
number
required
The line number (0-based).

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getNextWordBoundary

Finds the next word boundary from the cursor. 
getNextWordBoundary(): LogicalCursor
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return
LogicalCursor
The position of the next word boundary.

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getPrevWordBoundary

Finds the previous word boundary from the cursor. 
getPrevWordBoundary(): LogicalCursor
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return
LogicalCursor
The position of the previous word boundary.

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getEOL

Gets the end-of-line position for the current line. 
getEOL(): LogicalCursor
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return
LogicalCursor
The end-of-line position.

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Position Conversion

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offsetToPosition

Converts a character offset to a line/column position. 
offsetToPosition(offset: number): { row: number; col: number } | null
​
offset
number
required
The character offset.
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return
{ row: number; col: number } | null
The row/column position or null if invalid offset.

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positionToOffset

Converts a line/column position to a character offset. 
positionToOffset(row: number, col: number): number
​
row
number
required
The row number (0-based).
​
col
number
required
The column number (0-based).
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return
number
The character offset.

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getLineStartOffset

Gets the character offset of the start of a line. 
getLineStartOffset(row: number): number
​
row
number
required
The row number (0-based).
​
return
number
The character offset of the line start.

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Undo/Redo

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undo

Undoes the last edit operation. 
undo(): string | null
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return
string | null
Metadata about the undo operation or null if nothing to undo.

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redo

Redoes the last undone operation. 
redo(): string | null
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return
string | null
Metadata about the redo operation or null if nothing to redo.

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canUndo

Checks if there are operations available to undo. 
canUndo(): boolean
​
return
boolean
True if undo is available.

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canRedo

Checks if there are operations available to redo. 
canRedo(): boolean
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return
boolean
True if redo is available.

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clearHistory

Clears the entire undo/redo history. 
clearHistory(): void

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Styling

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setDefaultFg

Sets the default foreground color. 
setDefaultFg(fg: RGBA | null): void
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fg
RGBA | null
required
The foreground color or null to clear.

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setDefaultBg

Sets the default background color. 
setDefaultBg(bg: RGBA | null): void
​
bg
RGBA | null
required
The background color or null to clear.

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setDefaultAttributes

Sets default text attributes (bold, italic, etc.). 
setDefaultAttributes(attributes: number | null): void
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attributes
number | null
required
Bitfield of text attributes or null to clear.

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resetDefaults

Resets all default styling to original values. 
resetDefaults(): void

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setSyntaxStyle

Sets the syntax highlighting style. 
setSyntaxStyle(style: SyntaxStyle | null): void
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style
SyntaxStyle | null
required
The syntax style or null to disable.

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getSyntaxStyle

Gets the current syntax highlighting style. 
getSyntaxStyle(): SyntaxStyle | null
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return
SyntaxStyle | null
The current syntax style or null if none is set.

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Highlights

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addHighlight

Adds a highlight to a specific line by column positions. 
addHighlight(lineIdx: number, highlight: Highlight): void
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lineIdx
number
required
The line index (0-based).
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highlight
Highlight
required
The highlight definition with start/end columns.

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addHighlightByCharRange

Adds a highlight using absolute character offsets. 
addHighlightByCharRange(highlight: Highlight): void
​
highlight
Highlight
required
The highlight definition with start/end character offsets.

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removeHighlightsByRef

Removes all highlights with a specific reference ID. 
removeHighlightsByRef(hlRef: number): void
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hlRef
number
required
The highlight reference ID.

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clearLineHighlights

Clears all highlights on a specific line. 
clearLineHighlights(lineIdx: number): void
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lineIdx
number
required
The line index (0-based).

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clearAllHighlights

Removes all highlights from the buffer. 
clearAllHighlights(): void

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getLineHighlights

Retrieves all highlights for a specific line. 
getLineHighlights(lineIdx: number): Array<Highlight>
​
lineIdx
number
required
The line index (0-based).
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return
Array<Highlight>
Array of highlights on the line.

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Memory Management

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clear

Clears the buffer content. 
clear(): void

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destroy

Destroys the buffer and frees native resources. 
destroy(): void

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debugLogRope

Logs the internal rope data structure for debugging. 
debugLogRope(): void

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Types

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LogicalCursor

interface LogicalCursor {
  row: number
  col: number
  offset: number
}
​
row
number
required
The row position (0-based).
​
col
number
required
The column position (0-based).
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offset
number
required
The character offset from start of buffer.

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Events

EditBuffer extends EventEmitter and emits native events. Events are prefixed with eb_ internally but exposed without the prefix.

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Example

import { EditBuffer } from "@opentui/core"

// Create an edit buffer
const buffer = EditBuffer.create("wcwidth")

// Set initial text
buffer.setText("Hello, World!")

// Insert text at cursor
buffer.insertText(" Welcome to OpenTUI.")

// Move cursor
buffer.moveCursorLeft()
buffer.moveCursorUp()

// Get cursor position
const pos = buffer.getCursorPosition()
console.log(`Cursor at ${pos.row}:${pos.col}`)

// Undo and redo
buffer.undo()
if (buffer.canRedo()) {
  buffer.redo()
}

// Get text
const text = buffer.getText()
console.log(text)

// Clean up
buffer.destroy()

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