wip

packages/frontend-embed/vite.json5.ts

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+// Original: https://github.com/rollup/plugins/tree/8835dd2aed92f408d7dc72d7cc25a9728e16face/packages/json
+
+import JSON5 from 'json5';
+import { Plugin } from 'rollup';
+import { createFilter, dataToEsm } from '@rollup/pluginutils';
+import { RollupJsonOptions } from '@rollup/plugin-json';
+
+// json5 extends SyntaxError with additional fields (without subclassing)
+// https://github.com/json5/json5/blob/de344f0619bda1465a6e25c76f1c0c3dda8108d9/lib/parse.js#L1111-L1112
+interface Json5SyntaxError extends SyntaxError {
+	lineNumber: number;
+	columnNumber: number;
+}
+
+export default function json5(options: RollupJsonOptions = {}): Plugin {
+	const filter = createFilter(options.include, options.exclude);
+	const indent = 'indent' in options ? options.indent : '\t';
+
+	return {
+		name: 'json5',
+
+		// eslint-disable-next-line no-shadow
+		transform(json, id) {
+			if (id.slice(-6) !== '.json5' || !filter(id)) return null;
+
+			try {
+				const parsed = JSON5.parse(json);
+				return {
+					code: dataToEsm(parsed, {
+						preferConst: options.preferConst,
+						compact: options.compact,
+						namedExports: options.namedExports,
+						indent,
+					}),
+					map: { mappings: '' },
+				};
+			} catch (err) {
+				if (!(err instanceof SyntaxError)) {
+					throw err;
+				}
+				const message = 'Could not parse JSON5 file';
+				const { lineNumber, columnNumber } = err as Json5SyntaxError;
+				this.warn({ message, id, loc: { line: lineNumber, column: columnNumber } });
+				return null;
+			}
+		},
+	};
+}