Function rewriteBody

packages/tooling/src/vite.plugin.transform.ts:65–95

(body: Statement[], ms: MagicString)

}

function rewriteBody(body: Statement[], ms: MagicString): void {
    let open: { id: string; lastStmtEnd: number } | null = null;

    for (const stmt of body) {
        if (isElementStyleHelperUsing(stmt)) {
            if (open) {
                ms.appendLeft(open.lastStmtEnd, ` } finally { ${open.id}?.[Symbol.dispose]?.(); }`);
            }

            const idNode = stmt.declarations[0].id;
            if (idNode.type !== 'Identifier') {
                // destructured `using` is not supported.
                open = null;
                continue;
            }
            const name = (idNode as IdentifierName).name;

            // `using` is 5 chars; replace with `const`
            ms.update(stmt.start, stmt.start + 5, 'const');
            ms.appendLeft(stmt.end, ' try {');

            open = { id: name, lastStmtEnd: stmt.end };
        } else if (open) {
            open.lastStmtEnd = stmt.end;
        }
    }

    if (open) {
        ms.appendLeft(open.lastStmtEnd, ` } finally { ${open.id}?.[Symbol.dispose]?.(); }`);
    }
}

function isElementStyleHelperUsing(
    stmt: Statement