Wrapper function for gulp stream pipelines using highland.js (usage here: wrap markdown html output into a handlebars template)

gulpfile.js

const h = require("highland")
const handlebars = require("handlebars")

// handlebars wrapper pipeline for gulp object stream
const wrapIt = h.pipeline(function (stream) {
   return h(stream)  // wrap node stream into a highland stream
      // .tap(vinylObject => console.log(vinylObject.path))
      .map(function (vinylObject) {
         const data = vinylObject.contents.toString() // convert marktdown html to string
         const tpl = fs.readFileSync(tplFile, "utf8") // read handlebars template
         const fn = handlebars.compile(tpl) // compile template to fn
         const data2 = fn({md: data}) // inject markdown html into template
         vinylObject.contents = Buffer.from(data2) // update gulp vinyl object 
         return vinylObject
      })
      .toNodeStream({objectMode: true}) // convert to normal node stream so gulp can handle it
})

gulp.task("docs", function () {
   return gulp.src(docFile)
      .pipe(marked())
      .pipe(wrapIt)
      .pipe(gulp.dest(docDirDist))
})