gulpfile.js

'use strict';
const gulp = require('gulp');
const insert = require('gulp-insert');
const rename = require('gulp-rename');
const template = require('gulp-template');

// Compile all *.ejs files to pre-compiled templates and append *.js to the filename.
gulp.task('templates-cjs', () =>
  gulp.src('./src/**/*.ejs')
    .pipe(template.precompile({
      evaluate: /\{%([\s\S]+?)%\}/g,
      interpolate: /\{\{([\s\S]+?)\}\}/g,
      escape: /\{\{\{([\s\S]+?)\}\}\}/g,
      variable: 'ctx'
    }))
    .pipe(insert.prepend('Object.defineProperty(exports, "__esModule", {\n' +
    '  value: true\n' +
    '});\n' +
    'exports.default='))
    .pipe(rename({
      extname: '.ejs.js'
    }))
    .pipe(gulp.dest('lib/cjs'))
);

gulp.task('templates-mjs', () =>
  gulp.src('./src/**/*.ejs')
    .pipe(template.precompile({
      evaluate: /\{%([\s\S]+?)%\}/g,
      interpolate: /\{\{([\s\S]+?)\}\}/g,
      escape: /\{\{\{([\s\S]+?)\}\}\}/g,
      variable: 'ctx'
    }))
    .pipe(insert.prepend('export default '))
    .pipe(rename({
      extname: '.ejs.js'
    }))
    .pipe(gulp.dest('lib/mjs'))
);

gulp.task('templates', gulp.parallel(['templates-cjs', 'templates-mjs']));