import type { Message, Metafile } from 'esbuild';
/**
 * Builds an ECMAScript module (ESM) bundle for browser use using `esbuild`.
 *
 * This function:
 * - Ensures `esbuild` is available.
 * - Deletes the existing output file if it exists.
 * - Builds the input file with optimizations: minification, tree-shaking, etc.
 * - Returns the esbuild `metafile`, version, and any build errors or warnings.
 *
 * @param {Object} options - Build configuration.
 * @param {string} options.infile - The path to the input file to be bundled.
 * @param {string} options.outfile - The path where the output bundle should be written.
 * @param {Object<string, string>} [options.banner] - Optional banner to prepend to the generated file.
 *
 * @returns {Promise<{
 *   metafile: Metafile,
 *   errors: Message[],
 *   warnings: Message[],
 *   version: string
 * }>} An object containing the esbuild metafile, build errors/warnings, and the version of esbuild used.
 *
 * @throws Will exit the process if `esbuild` is not installed.
 */
export declare const buildEsm: ({ infile, outfile, banner }: {
    infile: string;
    outfile: string;
    banner?: {
        [type: string]: string;
    };
}) => Promise<{
    metafile: Metafile;
    errors: Message[];
    warnings: Message[];
    version: string;
}>;