Function rewriteTopLevelAwait

valdi/vscode_debugger/src/common/sourceUtils.ts:75–186

(code: string)

}

export function rewriteTopLevelAwait(code: string): string | undefined {
  // Basic idea is to wrap code in async function, which
  // we can await and expose side-effects outside of the function.
  // See "rewriteTopLevelAwait" test for examples.
  code = '(async () => {' + code + '\n})()';
  let body: ts.Block;
  try {
    const sourceFile = ts.createSourceFile(
      'file.js',
      code,
      ts.ScriptTarget.ESNext,
      /*setParentNodes */ true,
    );
    // eslint-disable-next-line
    body = (sourceFile.statements[0] as any)['expression']['expression']['expression'][
      'body'
    ] as ts.Block;
  } catch (e) {
    return;
  }

  const changes: { start: number; end: number; text: string }[] = [];
  let containsAwait = false;
  let containsReturn = false;

  function traverse(node: ts.Node) {
    switch (node.kind) {
      case ts.SyntaxKind.ClassDeclaration:
        // Expose "class Foo" as "Foo=class Foo"
        const cd = node as ts.ClassDeclaration;
        if (cd.parent === body && cd.name)
          changes.push({ text: cd.name.text + '=', start: cd.pos, end: cd.pos });
        break;
      case ts.SyntaxKind.FunctionDeclaration:
        // Expose "function foo(..." as "foo=function foo(..."
        const fd = node as ts.FunctionDeclaration;
        if (fd.name) changes.push({ text: fd.name.text + '=', start: fd.pos, end: fd.pos });
        return;
      case ts.SyntaxKind.FunctionExpression:
      case ts.SyntaxKind.ArrowFunction:
      case ts.SyntaxKind.MethodDeclaration:
        // Do not recurse into functions.
        return;
      case ts.SyntaxKind.AwaitExpression:
        containsAwait = true;
        break;
      case ts.SyntaxKind.ForOfStatement:
        if ((node as ts.ForOfStatement).awaitModifier) containsAwait = true;
        break;
      case ts.SyntaxKind.ReturnStatement:
        containsReturn = true;
        break;
      case ts.SyntaxKind.VariableDeclarationList:
        // Expose "var foo=..." as void(foo=...)
        const vd = node as ts.VariableDeclarationList;

        let s = code.substr(vd.pos);
        let skip = 0;