Bring compiler into Astro (#4)

* include source compiler

* Import from JS

* Conditionally use the instance contents

Co-authored-by: Fred K. Schott <fkschott@gmail.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/src/compiler/utils/get_code_frame.ts b/src/compiler/utils/get_code_frame.ts
new file mode 100644
index 000000000..1097f5b3d
--- /dev/null
+++ b/src/compiler/utils/get_code_frame.ts
@@ -0,0 +1,31 @@
+function tabs_to_spaces(str: string) {
+	return str.replace(/^\t+/, match => match.split('\t').join('  '));
+}
+
+export default function get_code_frame(
+	source: string,
+	line: number,
+	column: number
+) {
+	const lines = source.split('\n');
+
+	const frame_start = Math.max(0, line - 2);
+	const frame_end = Math.min(line + 3, lines.length);
+
+	const digits = String(frame_end + 1).length;
+
+	return lines
+		.slice(frame_start, frame_end)
+		.map((str, i) => {
+			const isErrorLine = frame_start + i === line;
+			const line_num = String(i + frame_start + 1).padStart(digits, ' ');
+
+			if (isErrorLine) {
+				const indicator = ' '.repeat(digits + 2 + tabs_to_spaces(str.slice(0, column)).length) + '^';
+				return `${line_num}: ${tabs_to_spaces(str)}\n${indicator}`;
+			}
+
+			return `${line_num}: ${tabs_to_spaces(str)}`;
+		})
+		.join('\n');
+}