index.js 1.6 KB

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  1. "use strict";
  2. Object.defineProperty(exports, "__esModule", {
  3. value: true
  4. });
  5. exports.default = void 0;
  6. var _helperPluginUtils = require("@babel/helper-plugin-utils");
  7. var _pluginSyntaxNullishCoalescingOperator = _interopRequireDefault(require("@babel/plugin-syntax-nullish-coalescing-operator"));
  8. var _core = require("@babel/core");
  9. function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
  10. var _default = (0, _helperPluginUtils.declare)((api, {
  11. loose = false
  12. }) => {
  13. api.assertVersion(7);
  14. return {
  15. name: "proposal-nullish-coalescing-operator",
  16. inherits: _pluginSyntaxNullishCoalescingOperator.default,
  17. visitor: {
  18. LogicalExpression(path) {
  19. const {
  20. node,
  21. scope
  22. } = path;
  23. if (node.operator !== "??") {
  24. return;
  25. }
  26. let ref = scope.maybeGenerateMemoised(node.left);
  27. let assignment;
  28. if (ref === null) {
  29. ref = node.left;
  30. assignment = _core.types.cloneNode(node.left);
  31. } else {
  32. assignment = _core.types.assignmentExpression("=", ref, node.left);
  33. }
  34. path.replaceWith(_core.types.conditionalExpression(loose ? _core.types.binaryExpression("!=", assignment, _core.types.nullLiteral()) : _core.types.logicalExpression("&&", _core.types.binaryExpression("!==", assignment, _core.types.nullLiteral()), _core.types.binaryExpression("!==", _core.types.cloneNode(ref), scope.buildUndefinedNode())), _core.types.cloneNode(ref), node.right));
  35. }
  36. }
  37. };
  38. });
  39. exports.default = _default;