code: function getImportSources(filePath, parserOpts, extensions) {
    let importSources = [];
    if (extensions.indexOf(path.extname(filePath).replace('.', ''))> -1 ) {
      let file = loadFileSync(filePath, parserOpts);
      for (let item of file.path.get('body')) {
        if (item.isImportDeclaration() || (item.isExportDeclaration() && item.node.source)) {
          importSources.push(item.node.source.value);
        }
      }
    }
    
    return importSources;
  }
docs: /*::
  import type { BabelParserOptions } from 'babel-flow-types';
  
  export type ParserOptions = BabelParserOptions;
  export type ResolveOptions = {
  package?: Object,
  extensions?: Array<string>,
  readFile?: Function,
  isFile?: Function,
  packageFilter?: Function,
  pathFilter?: Function,
  paths?: Array<string>,
  moduleDirectory?: string | Array<string>,
  };