gulp.chunks.js

import gulpJsonTransform from 'gulp-json-transform';

function patchChunks() {
  return gulp.src(path.resolve(config.output.path, 'manifest.json'))
    .pipe(gulpJsonTransform((data) => {
      data.background.scripts = ...
      data.content_scripts = ....
      // ...
      return data;
    }))
    .pipe(gulp.dest(config.output.path));
}