code: function getKeyMapNode({ id, programPath, types: t }) {
    return programPath.node.body
      .filter(t.isExportNamedDeclaration)
      .filter(n => t.isVariableDeclaration(n.declaration)
                            && n.declaration.kind === 'const'
                            && n.declaration.declarations.length === 1
                            && n.declaration.declarations[0].id.name === id)
      .map(n => n.declaration.declarations[0].init)[0];
  }
docs: returns rhs of export const <id> = {};