Flutter ETS API Documentation v1.0.0

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Class: FlutterTextUtils

Utility class for text processing operations, including Unicode code point handling, emoji detection, and text offset calculations.

Constructors

Constructor

new FlutterTextUtils(): FlutterTextUtils

Returns

FlutterTextUtils

Methods

charCount()

static charCount(codePoint): number

Gets the number of UTF-16 code units required to represent a Unicode code point.

Parameters

codePoint

number

The Unicode code point

Returns

number

1 for BMP characters (0x0000-0xFFFF), 2 for supplementary characters (0x10000-0x10FFFF)

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codePointAt()

static codePointAt(text, offset): number

Gets the Unicode code point at the specified offset in the text. Handles surrogate pairs correctly.

Parameters

text

string

The text to examine

offset

number

The offset position

Returns

number

The Unicode code point at the offset

Throws

RangeError if the offset is out of range

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codePointBefore()

static codePointBefore(text, offset): number

Gets the Unicode code point before the specified offset in the text. Handles surrogate pairs correctly.

Parameters

text

string

The text to examine

offset

number

The offset position

Returns

number

The Unicode code point before the offset

Throws

RangeError if the offset is out of range

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getImePreviewBackspaceDeleteRange()

static getImePreviewBackspaceDeleteRange(text, offset): ImePreviewBackspaceRange

One preview Backspace step: delete [delStart, delEnd) so a lone IME ' left of the caret does not expand the removal to [delStart, caret) (which would swallow the previous letter too). When [plain, offset) is apostrophe-only, deletes one grapheme cluster immediately before that run: [getOffsetBefore(text, plain), plain) instead of […, offset).

Parameters

text

string

offset

number

Returns

ImePreviewBackspaceRange

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getOffsetAfter()

static getOffsetAfter(text, offset): number

Gets the offset after the current position, handling complex Unicode sequences such as emojis, regional indicators, keycaps, and variation selectors.

Parameters

text

string

The text to examine

offset

number

The current offset position

Returns

number

The offset after the current position, accounting for Unicode sequences

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getOffsetAfterForImePreview()

static getOffsetAfterForImePreview(text, offset): number

Same as getOffsetAfter, but if [offset, end) is only consecutive ' (IME separators), extend once more so ' is not counted alone as one forward-delete step.

Parameters

text

string

offset

number

Returns

number

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getOffsetBefore()

static getOffsetBefore(text, offset): number

Gets the offset before the current position, handling complex Unicode sequences such as emojis, regional indicators, keycaps, and variation selectors.

Parameters

text

string

The text to examine

offset

number

The current offset position

Returns

number

The offset before the current position, accounting for Unicode sequences

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isEmoji()

static isEmoji(code): boolean

Checks if a Unicode code point represents an emoji.

Parameters

code

number

The Unicode code point to check

Returns

boolean

True if the code point is an emoji, false otherwise

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isEmojiModifier()

static isEmojiModifier(code): boolean

Checks if a Unicode code point represents an emoji modifier.

Parameters

code

number

The Unicode code point to check

Returns

boolean

True if the code point is an emoji modifier, false otherwise

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isEmojiModifierBase()

static isEmojiModifierBase(code): boolean

Checks if a Unicode code point represents an emoji modifier base.

Parameters

code

number

The Unicode code point to check

Returns

boolean

True if the code point is an emoji modifier base, false otherwise

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isKeycapBase()

static isKeycapBase(code): boolean

Checks if a Unicode code point is a keycap base character (0-9, #, *).

Parameters

code

number

The Unicode code point to check

Returns

boolean

True if the code point is a keycap base, false otherwise

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isRegionalIndicatorSymbol()

static isRegionalIndicatorSymbol(code): boolean

Checks if a Unicode code point represents a regional indicator symbol.

Parameters

code

number

The Unicode code point to check

Returns

boolean

True if the code point is a regional indicator symbol, false otherwise

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isTagSpecChar()

static isTagSpecChar(code): boolean

Checks if a Unicode code point is a tag specification character.

Parameters

code

number

The Unicode code point to check

Returns

boolean

True if the code point is a tag specification character, false otherwise

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isVariationSelector()

static isVariationSelector(code): boolean

Checks if a Unicode code point represents a variation selector.

Parameters

code

number

The Unicode code point to check

Returns

boolean

True if the code point is a variation selector, false otherwise