/**
 * @license
 * Copyright 2021 Google LLC
 * SPDX-License-Identifier: BSD-3-Clause
 */
import ts from 'typescript';
/**
 * The content of the comments generated by the preserveBlankLines transformer.
 *
 * Contains a fixed random string that is meaningless and serves only to make
 * the chance of collisions negligible.
 */
export declare const BLANK_LINE_PLACEHOLDER_COMMENT = "__BLANK_LINE_PLACEHOLDER_G1JVXUEBNCL6YN5NFE13MD1PT3H9OIHB__";
/**
 * A regular expression that matches the comments generated by the
 * preserveBlankLines transformer, including the leading "//" and preceding
 * indentation.
 */
export declare const BLANK_LINE_PLACEHOLDER_COMMENT_REGEXP: RegExp;
/**
 * TypeScript transformer that replaces blank lines in the original source with
 * a unique comment, allowing original line formatting to be preserved after
 * transform using a simple search-and-replace.
 *
 * For example, given:
 *
 *   import 'foo';
 *
 *   class Foo {
 *     foo() {}
 *
 *     bar() {}
 *   }
 *
 * Produces:
 *
 *   import 'foo';
 *   //__BLANK_LINE_PLACEHOLDER_G1JVXUEBNCL6YN5NFE13MD1PT3H9OIHB__
 *   class Foo {
 *     foo() {}
 *     //__BLANK_LINE_PLACEHOLDER_G1JVXUEBNCL6YN5NFE13MD1PT3H9OIHB__
 *     bar() {}
 *   }
 *
 * These placeholder comments can be replaced with newlines after transform with
 * the `BLANK_LINE_PLACEHOLDER_COMMENT_REGEXP` regexp, or with any equivalent
 * search-and-replace operation for the comment style shown above.
 */
export declare function preserveBlankLinesTransformer(): ts.TransformerFactory<ts.SourceFile>;