code: function resolveAbsolute(base, filePath) {
  	return getBasePath(base)
  	.then(basePath => new Promise((resolve, reject) => {
  		filePath = filePath.replace(reAbsolute, '');
  
  		const next = ctx => {
  			tryFile(path.resolve(ctx, filePath))
  			.then(resolve, () => {
  				const dir = path.dirname(ctx);
  				if (!dir || dir === ctx) {
  					return reject(`Unable to locate absolute file ${filePath}`);
  				}
  
  				next(dir);
  			});
  		};
  
  		next(basePath);
  	}));
  }
docs: Resolves absolute file path agaist given editor: tries to find file in every
  parent of editor’s file
  @param  {TextEditor|String} base
  @param  {String}            filePath
  @return {Promise}