/**
 * Copyright 2018 The AMP HTML Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { ChunkTransform } from '../../transform';
import { TransformInterface } from '../../types';
import MagicString from 'magic-string';
export default class ImportTransform extends ChunkTransform implements TransformInterface {
    private importedExternalsSyntax;
    private importedExternalsLocalNames;
    dynamicImportPresent: boolean;
    name: string;
    /**
     * Generate externs for local names of external imports.
     * Otherwise, advanced mode compilation will fail since the reference is unknown.
     * @return string representing content of generated extern.
     */
    extern(): string | null;
    /**
     * Before Closure Compiler modifies the source, we need to ensure external imports have been removed
     * since Closure will error out when it encounters them.
     * @param code source to parse, and modify
     * @return modified input source with external imports removed.
     */
    pre: (fileName: string, source: MagicString) => Promise<MagicString>;
    /**
     * After Closure Compiler has modified the source, we need to re-add the external imports
     * @param code source post Closure Compiler Compilation
     * @return Promise containing the repaired source
     */
    post(fileName: string, source: MagicString): Promise<MagicString>;
}