text: "use strict";
  var __importStar = (this && this.__importStar) || function (mod) {
      if (mod && mod.__esModule) return mod;
      var result = {};
      if (mod != null) for (var k in mod) if (Object.hasOwnProperty.call(mod, k)) result[k] = mod[k];
      result["default"] = mod;
      return result;
  };
  Object.defineProperty(exports, "__esModule", { value: true });
  const experimental_utils_1 = require("@typescript-eslint/experimental-utils");
  const util = __importStar(require("../util"));
  exports.default = util.createRule({
      name: 'prefer-nullish-coalescing',
      meta: {
          type: 'suggestion',
          docs: {
              description: 'Enforce the usage of the nullish coalescing operator instead of logical chaining',
              category: 'Best Practices',
              recommended: false,
              suggestion: true,
              requiresTypeChecking: true,
          },
          fixable: 'code',
          messages: {
              preferNullish: 'Prefer using nullish coalescing operator (`??`) instead of a logical or (`||`), as it is a safer operator.',
          },
          schema: [
              {
                  type: 'object',
                  properties: {
                      ignoreConditionalTests: {
                          type: 'boolean',
                      },
                      ignoreMixedLogicalExpressions: {
                          type: 'boolean',
                      },
                      forceSuggestionFixer: {
                          type: 'boolean',
                      },
                  },
                  additionalProperties: false,
              },
          ],
      },
      defaultOptions: [
          {
              ignoreConditionalTests: true,
              ignoreMixedLogicalExpressions: true,
              forceSuggestionFixer: false,
          },
      ],
      create(context, [{ ignoreConditionalTests, ignoreMixedLogicalExpressions, forceSuggestionFixer, },]) {
          const parserServices = util.getParserServices(context);
          const sourceCode = context.getSourceCode();
          const checker = parserServices.program.getTypeChecker();
          return {
              'LogicalExpression[operator = "||"]'(node) {
                  const tsNode = parserServices.esTreeNodeToTSNodeMap.get(node);
                  const type = checker.getTypeAtLocation(tsNode.left);
                  const isNullish = util.isNullableType(type, { allowUndefined: true });
                  if (!isNullish) {
                      return;
                  }
                  if (ignoreConditionalTests === true && isConditionalTest(node)) {
                      return;
                  }
                  const isMixedLogical = isMixedLogicalExpression(node);
                  if (ignoreMixedLogicalExpressions === true && isMixedLogical) {
                      return;
                  }
                  const barBarOperator = util.nullThrows(sourceCode.getTokenAfter(node.left, token => token.type === experimental_utils_1.AST_TOKEN_TYPES.Punctuator &&
                      token.value === node.operator), util.NullThrowsReasons.MissingToken('operator', node.type));
                  function* fix(fixer) {
                      if (node.parent && util.isLogicalOrOperator(node.parent)) {
                          // '&&' and '??' operations cannot be mixed without parentheses (e.g. a && b ?? c)
                          if (node.left.type === experimental_utils_1.AST_NODE_TYPES.LogicalExpression &&
                              !util.isLogicalOrOperator(node.left.left)) {
                              yield fixer.insertTextBefore(node.left.right, '(');
                          }
                          else {
                              yield fixer.insertTextBefore(node.left, '(');
                          }
                          yield fixer.insertTextAfter(node.right, ')');
                      }
                      yield fixer.replaceText(barBarOperator, '??');
                  }
                  const fixer = isMixedLogical || forceSuggestionFixer
                      ? // suggestion instead for cases where we aren't sure if the fixer is completely safe
                          {
                              suggest: [
                                  {
                                      messageId: 'preferNullish',
                                      fix,
                                  },
                              ],
                          }
                      : { fix };
                  context.report(Object.assign({ node: barBarOperator, messageId: 'preferNullish' }, fixer));
              },
          };
      },
  });
  function isConditionalTest(node) {
      const parents = new Set([node]);
      let current = node.parent;
      while (current) {
          parents.add(current);
          if ((current.type === experimental_utils_1.AST_NODE_TYPES.ConditionalExpression ||
              current.type === experimental_utils_1.AST_NODE_TYPES.DoWhileStatement ||
              current.type === experimental_utils_1.AST_NODE_TYPES.IfStatement ||
              current.type === experimental_utils_1.AST_NODE_TYPES.ForStatement ||
              current.type === experimental_utils_1.AST_NODE_TYPES.WhileStatement) &&
              parents.has(current.test)) {
              return true;
          }
          if ([
              experimental_utils_1.AST_NODE_TYPES.ArrowFunctionExpression,
              experimental_utils_1.AST_NODE_TYPES.FunctionExpression,
          ].includes(current.type)) {
              /**
               * This is a weird situation like:
               * `if (() => a || b) {}`
               * `if (function () { return a || b }) {}`
               */
              return false;
          }
          current = current.parent;
      }
      return false;
  }
  function isMixedLogicalExpression(node) {
      const seen = new Set();
      const queue = [node.parent, node.left, node.right];
      for (const current of queue) {
          if (seen.has(current)) {
              continue;
          }
          seen.add(current);
          if (current && current.type === experimental_utils_1.AST_NODE_TYPES.LogicalExpression) {
              if (current.operator === '&&') {
                  return true;
              }
              else if (current.operator === '||') {
                  // check the pieces of the node to catch cases like `a || b || c && d`
                  queue.push(current.parent, current.left, current.right);
              }
          }
      }
      return false;
  }
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