extract-base-iterator/README.md

Base iterator for extract iterators like tar-iterator and zip-iterator

## extract-base-iterator

Base iterator for extract iterators like tar-iterator and zip-iterator.

// asyncIterator

```js
var assert = require('assert');
var BaseIterator = require('extract-base-iterator'));

// extend BaseIterator (see tests, tar-iterator, zip-iterator for examples)

(async function() {
  var iterator = new YourIterator();

  try {
    const links = [];
    for await (const entry of iterator) {
      if (entry.type === 'link') links.unshift(entry);
      else if (entry.type === 'symlink') links.push(entry);
      else await entry.create(dest, options);
    }

    // create links after directories and files
    for (const entry of links) await entry.create(dest, options);
  } catch (err) {
    }

  iterator.destroy();
  iterator = null;
})();
```

// Async / Await

```js
var assert = require('assert');
var BaseIterator = require('extract-base-iterator'));

// extend BaseIterator (see tests, tar-iterator, zip-iterator for examples)

var iterator = new YourIterator();

// one by one
(async function() {
  let iterator = new YourIterator();

  try {
    const links = [];
    for await (const entry of iterator) {
      if (entry.type === 'link') links.unshift(entry);
      else if (entry.type === 'symlink') links.push(entry);
      else await entry.create(dest, options);
    }

    // create links after directories and files
    for (const entry of links) await entry.create(dest, options);
  } catch (err) {
    }

  iterator.destroy();
  iterator = null;
})();

// infinite concurrency
(async function() {
  let iterator = new YourIterator();

  try {
    const links = [];
    await iterator.forEach(
      async function (entry) {
        if (entry.type === 'link') links.unshift(entry);
        else if (entry.type === 'symlink') links.push(entry);
        else await entry.create(dest, options);
      },
      { concurrency: Infinity }
    );

    // create links after directories and files
    for (const entry of links) await entry.create(dest, options);
  } catch (err) {
    aseert.ok(!err);
  }

  iterator.destroy();
  iterator = null;
})();
```

// Callbacks

```js
var assert = require('assert');
var Queue = require('queue-cb');
var BaseIterator = require('extract-base-iterator'));

// extend BaseIterator (see tests, tar-iterator, zip-iterator for examples)

var iterator = new YourIterator();

// one by one
var links = [];
iterator.forEach(
  function (entry, callback) {
    if (entry.type === 'link') {
      links.unshift(entry);
      callback();
    } else if (entry.type === 'symlink') {
      links.push(entry);
      callback();
    } else entry.create(dest, options, callback);
  },
  { callbacks: true, concurrency: 1 },
  function (err) {
  
    // create links after directories and files
    var queue = new Queue();
    for (var index = 0; index < links.length; index++) {
      var entry = links[index];
      queue.defer(entry.create.bind(entry, dest, options));
    }
    queue.await(callback);

    iterator.destroy();
    iterator = null;
  }
);
```