positionAt() — astro Function Reference

Architecture documentation for the positionAt() function in utils.ts from the astro codebase.

Function typescript CoreAstro RenderingEngine calls 1

Entity Profile

CoreAstro→ RenderingEngine→ positionAt() — astro Function Reference

Dependency Diagram

graph TD
  b70271ae_4018_71fe_f092_f1b7ce0476d7["positionAt()"]
  a37e7fee_e130_2a00_6f99_81cf3cf65c83["utils.ts"]
  b70271ae_4018_71fe_f092_f1b7ce0476d7 -->|defined in| a37e7fee_e130_2a00_6f99_81cf3cf65c83
  d8849cd9_ed6a_f4bb_959f_98a475c3e22e["getLineOffsets()"]
  b70271ae_4018_71fe_f092_f1b7ce0476d7 -->|calls| d8849cd9_ed6a_f4bb_959f_98a475c3e22e
  style b70271ae_4018_71fe_f092_f1b7ce0476d7 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/astro/src/core/errors/utils.ts lines 11–50

export function positionAt(
	offset: number,
	text: string,
): {
	line: number;
	column: number;
} {
	const lineOffsets = getLineOffsets(text);
	offset = Math.max(0, Math.min(text.length, offset));

	let low = 0;
	let high = lineOffsets.length;
	if (high === 0) {
		return {
			line: 0,
			column: offset,
		};
	}

	while (low <= high) {
		const mid = Math.floor((low + high) / 2);
		const lineOffset = lineOffsets[mid];

		if (lineOffset === offset) {
			return {
				line: mid,
				column: 0,
			};
		} else if (offset > lineOffset) {
			low = mid + 1;
		} else {
			high = mid - 1;
		}
	}

	// low is the least x for which the line offset is larger than the current offset
	// or array.length if no line offset is larger than the current offset
	const line = low - 1;
	return { line, column: offset - lineOffsets[line] };
}