Gulp control output based on data from an earlier pipe

Question

I have been trying to find a way with gulp to only write out certain files based on yaml data I am collecting in the pipe. I have been able to see the file's data, but not able to get the output I expect.

In this task, I am collecting a glob of markdown files, and passing them into a pipe that reads the yaml using gulp-data, and then adds some other data to it. I then pipe it through Swig.

I'm trying to add some sort of conditional element before I pipe into gulp.dest. I found this example which got me to where I am currently.

The closest I've gotten is below:

  .pipe(tap(function(file) {
    if (new Date(file.data.date) >= new Date(buildRange)) {
      console.log(file.path);
      gulp.src(file.path)
        .pipe(gulp.dest(config.paths.dest + '/underreview/'));
    }
  }))

What I've gotten from the console.log command is correct (it shows 2 of 50 files). But nothing gets written to the destination. If I move the gulp.dest outside of this pipe, all files get written.

I've tried using gulp-if or gulp-ignore, but have been unable to get the file.data.date into either of those modules.

---

Edited: Here's the complete task

module.exports = function(gulp, config, env) {


var gulpSwig = require('gulp-swig'),
    swig = require('swig'),
    data = require('gulp-data'),
    matter = require('gray-matter'),
    runSequence = require('run-sequence'),
    // BrowserSync
    reload = config.browserSync.reload,
    _ = require('lodash'),
    Path = require('path'),
    requireDir = require('require-dir'),
    marked = require('marked'),
    readingTime = require('reading-time'),
    postsData = [],
    postsTags = [],
    pdate = null,
    buildRange = new Date(new Date().setDate(new Date().getDate()-14));
    sitebuilddate = null,
    through = require('through2'),
    gutil = require('gulp-util'),
    rename = require('gulp-rename'),
    File = require('vinyl'),
    $if = require('gulp-if'),
    ignore = require('gulp-ignore'),
    tap = require('gulp-tap');

  var opts = {
    defaults: {
      cache: false
    },
    setup: function(Swig) {
      Swig.setDefaults({
        loader: Swig.loaders.fs(config.paths.source + '/templates')});
    }
  };

  // Full of the compiled HTML file
  function targetPathFull(path, data) {
    return Path.join(Path.dirname(path), targetPath(data));
  }

gulp.task('templates2:under', function() {
    return gulp.src(config.paths.source + '/content/**/*.md')
      .pipe(data(function(file) {
        postData = [];
        var matterObject = matter(String(file.contents)), // extract front matter data
          type = matterObject.data.type, // page type
          body = matterObject.content,
          postData = matterObject.data,
          moreData = requireDir(config.paths.data),
          data = {},
          bodySwig;

        bodySwig = swig.compile(body, opts);
        // Use swig to render partials first
        body = bodySwig(data);
        // Process markdown
        if (Path.extname(file.path) === '.md') {
          body = marked(body);
        }
        // Inherit the correct template based on type
        if (type) {
          var compiled = _.template(
            "{% extends 'pages/${type}.html' %}{% block body %}${body}{% endblock %}"
            // Always use longform until a different template for different types is needed
            //"{% extends 'pages/longform.html' %}{% block body %}${body}{% endblock %}"
          );
          body = compiled({
            "type": type,
            "body": body
          });
        }

        file.path = targetPathFull(file.path, postData);
        moreData.path = targetPath(postData);
        _.merge(data, postData, moreData);

        data.url = data.site.domain + "/" + data.slug;
        // Copy the processed body text back into the file object so Gulp can keep piping
        file.contents = new Buffer(body);

        return data;
      }))
      .pipe(gulpSwig(opts))
      .pipe(tap(function(file) {
        if (new Date(file.data.date) >= new Date(buildRange)) {
          console.log(file.path);
          gulp.src(file.path)
            .pipe(gulp.dest(config.paths.dest + '/underreview/'));
        }
      }))
      .pipe(gulp.dest(config.paths.dest + '/underreview/'));  
  });
}

Answer 1

So, possibly not the best solution, but after some re-factoring I came up with this:

.pipe(gulp.dest(config.paths.dest + '/underreview/'))
      .pipe(tap(function(file) {
        if (new Date(file.data.date) < new Date(buildRange)) {
          console.log(file.data.path);
          del(config.paths.dest + '/underreview/' + file.data.path)
        }
      }))  

I moved the gulp-tap to after the output, and then I am deleting the file that was just written.