vercel/examples/aurelia/aurelia_project/tasks/environment.js

import project from '../aurelia.json';
import rename from 'gulp-rename';
import gulp from 'gulp';
import fs from 'fs';
import through from 'through2';
import { CLIOptions } from 'aurelia-cli';

function configureEnvironment() {
  let env = CLIOptions.getEnvironment();

  return gulp
    .src(
      `aurelia_project/environments/${env}${project.transpiler.fileExtension}`
    )
    .pipe(rename(`environment${project.transpiler.fileExtension}`))
    .pipe(
      through.obj(function(file, _, cb) {
        // https://github.com/aurelia/cli/issues/1031
        fs.unlink(`${project.paths.root}/${file.relative}`, function() {
          cb(null, file);
        });
      })
    )
    .pipe(gulp.dest(project.paths.root))
    .pipe(
      through.obj(function(file, enc, cb) {
        // https://github.com/webpack/watchpack/issues/25#issuecomment-287789288
        const now = Date.now() / 1000;
        const then = now - 10;
        fs.utimes(file.path, then, then, function(err) {
          if (err) throw err;
        });
        cb(null, file);
      })
    );
}

export default configureEnvironment;