Function rewriteTopLevelAwait

src/common/sourceUtils.ts:82–200

(code: string)

}

export function rewriteTopLevelAwait(code: string): string | undefined {
  let program: Program;
  try {
    // todo: strict needed due to https://github.com/acornjs/acorn/issues/988
    program = parseProgram(code);
  } catch (e) {
    return undefined;
  }

  const makeAssignment = (id: Identifier, rhs: Expression): ExpressionStatement => ({
    type: 'ExpressionStatement',
    expression: {
      type: 'AssignmentExpression',
      operator: '=',
      left: id,
      right: rhs,
    },
  });

  let containsAwait = false;
  let containsReturn = false;

  const replaced = replace(program, {
    enter(node, parent) {
      switch (node.type) {
        case 'ClassDeclaration':
          return {
            replace: makeAssignment(node.id || { type: 'Identifier', name: '_default' }, {
              ...node,
              type: 'ClassExpression',
            }),
          };
        case 'FunctionDeclaration':
          return {
            replace: makeAssignment(node.id || { type: 'Identifier', name: '_default' }, {
              ...node,
              type: 'FunctionExpression',
            }),
          };
        case 'FunctionExpression':
        case 'ArrowFunctionExpression':
        case 'MethodDefinition':
          return VisitorOption.Skip;
        case 'AwaitExpression':
          containsAwait = true;
          return;
        case 'ForOfStatement':
          if (node.await) {
            containsAwait = true;
          }
          return;
        case 'ReturnStatement':
          containsReturn = true;
          return;
        case 'VariableDeclaration':
          if (!parent || !('body' in parent) || !(parent.body instanceof Array)) {
            return;
          }