demo/typescript.js
function isSymbolUsedInExportAssignment(symbol) {
                    if (exportAssignmentSymbol === symbol) {
                        return true;
                    }
                    if (exportAssignmentSymbol && !!(exportAssignmentSymbol.flags & 8388608 /* Alias */)) {
                        // if export assigned symbol is alias declaration, resolve the alias
                        resolvedExportSymbol = resolvedExportSymbol || resolveAlias(exportAssignmentSymbol);
                        if (resolvedExportSymbol === symbol) {
                            return true;
                        }
                        // Container of resolvedExportSymbol is visible
                        return ts.forEach(resolvedExportSymbol.declarations, function (current) {
                            while (current) {
                                if (current === node) {
                                    return true;
                                }
                                current = current.parent;
                            }
                        });
                    }
                }
function isSymbolUsedInExportAssignment(symbol) {
                    if (exportAssignmentSymbol === symbol) {
                        return true;
                    }
                    if (exportAssignmentSymbol && !!(exportAssignmentSymbol.flags & 8388608 /* Alias */)) {
                        // if export assigned symbol is alias declaration, resolve the alias
                        resolvedExportSymbol = resolvedExportSymbol || resolveAlias(exportAssignmentSymbol);
                        if (resolvedExportSymbol === symbol) {
                            return true;
                        }
                        // Container of resolvedExportSymbol is visible
                        return ts.forEach(resolvedExportSymbol.declarations, function (current) {
                            while (current) {
                                if (current === node) {
                                    return true;
                                }
                                current = current.parent;
                            }
                        });
                    }
                }
Check if the symbol is used in export assignment