Babel Helper: Binary Assignment Operator Visitor Builder

import { declare } from '@babel/helper-plugin-utils';
import { buildBinaryAssignmentOperatorVisitor } from '@babel/helper-builder-binary-assignment-operator-visitor';

export default declare((api, options) => {
  api.assertVersion(7);

  // This helper builds a visitor that handles binary and assignment operators.
  // It can simplify transformations for operators like `+=`, `-=`, `&&=`, `??=` etc.
  // The helper typically expects a 'kind' (binary or assignment) and a map of operators
  // to visitor methods. Since the README is a TODO, this is an illustrative example
  // based on common Babel plugin patterns.

  // Example: A plugin to replace all `+=` operators with a function call.
  // This specific helper might be overkill for just one operator, but shows the pattern.
  // In a real scenario, you'd define methods for multiple operators.

  const visitor = buildBinaryAssignmentOperatorVisitor({
    operator(path) {
      // `path` is a NodePath for the operator expression (e.g., BinaryExpression, AssignmentExpression).
      const { node } = path;
      if (node.operator === '+=' && node.type === 'AssignmentExpression') {
        // Transform 'a += b' into 'assignAndAdd(a, b)'
        path.replaceWith(
          api.types.callExpression(
            api.types.identifier('assignAndAdd'),
            [node.left, node.right]
          )
        );
      }
    },
    // More specific operator handlers could be defined here
    // '+=_assignment'(path) { /* ... */ },
    // '+_binary'(path) { /* ... */ }
  });

  return {
    name: 'transform-binary-assignment-operators',
    visitor: {
      // The visitor is returned directly from the helper.
      // It usually contains handlers for 'BinaryExpression' and 'AssignmentExpression'.
      ...visitor
    },
  };
});