Function findTextCursor

packages/core/src/utils/cursor.ts:20–56

(
	cursor: number,
	deltaX: number,
	deltaY: number,
	value: string
)

}

export function findTextCursor(
	cursor: number,
	deltaX: number,
	deltaY: number,
	value: string
): number {
	const lines = value.split('\n');
	let cursorY = 0;
	let cursorX = cursor;

	for (const line of lines) {
		if (cursorX <= line.length) {
			break;
		}
		cursorX -= line.length + 1;
		cursorY++;
	}

	cursorY = Math.max(0, Math.min(lines.length - 1, cursorY + deltaY));

	cursorX = Math.min(cursorX, lines[cursorY].length) + deltaX;
	while (cursorX < 0 && cursorY > 0) {
		cursorY--;
		cursorX += lines[cursorY].length + 1;
	}
	while (cursorX > lines[cursorY].length && cursorY < lines.length - 1) {
		cursorX -= lines[cursorY].length + 1;
		cursorY++;
	}
	cursorX = Math.max(0, Math.min(lines[cursorY].length, cursorX));

	let newCursor = 0;
	for (let i = 0; i < cursorY; i++) {
		newCursor += lines[i].length + 1;
	}
	return newCursor + cursorX;
}