drop through2 dependency

use native stream.Transform instead

gulp.d/lib/gulp-prettier-eslint.js

@@ -1,9 +1,10 @@
 'use strict'
 
 const log = require('fancy-log')
-const { obj: map } = require('through2')
 const PluginError = require('plugin-error')
 const prettierEslint = require('prettier-eslint')
+const { Transform } = require('stream')
+const map = (transform) => new Transform({ objectMode: true, transform })
 
 module.exports = () => {
   const report = { changed: 0, unchanged: 0 }

gulp.d/tasks/build-preview-pages.js

@@ -9,11 +9,12 @@ Error.call = (self, ...args) => {
 const asciidoctor = require('asciidoctor.js')()
 const fs = require('fs-extra')
 const handlebars = require('handlebars')
-const { obj: map } = require('through2')
 const merge = require('merge-stream')
 const ospath = require('path')
 const path = ospath.posix
 const requireFromString = require('require-from-string')
+const { Transform } = require('stream')
+const map = (transform = () => {}, flush = undefined) => new Transform({ objectMode: true, transform, flush })
 const vfs = require('vinyl-fs')
 const yaml = require('js-yaml')
 
@@ -62,7 +63,7 @@ module.exports = (src, previewSrc, previewDest, sink = () => map()) => (done) =>
           })
         )
         .pipe(vfs.dest(previewDest))
-        .on('error', (e) => done)
+        //.on('error', done)
         .pipe(sink())
     )
 

gulp.d/tasks/build.js

@@ -7,7 +7,6 @@ const concat = require('gulp-concat')
 const cssnano = require('cssnano')
 const fs = require('fs-extra')
 const imagemin = require('gulp-imagemin')
-const { obj: map } = require('through2')
 const merge = require('merge-stream')
 const ospath = require('path')
 const path = ospath.posix
@@ -16,6 +15,8 @@ const postcssCalc = require('postcss-calc')
 const postcssImport = require('postcss-import')
 const postcssUrl = require('postcss-url')
 const postcssVar = require('postcss-custom-properties')
+const { Transform } = require('stream')
+const map = (transform) => new Transform({ objectMode: true, transform })
 const uglify = require('gulp-uglify')
 const vfs = require('vinyl-fs')
 

gulp.d/tasks/remove.js

@@ -1,7 +1,8 @@
 'use strict'
 
 const fs = require('fs-extra')
-const { obj: map } = require('through2')
+const { Transform } = require('stream')
+const map = (transform) => new Transform({ objectMode: true, transform })
 const vfs = require('vinyl-fs')
 
 module.exports = (files) => () =>