itemsjs/docs/lunr2-integration.md

Created to perform fast search on small json dataset (up to 1000 elements).

# Integration with Lunr 2.x

```js
const lunr = require('lunr');
const ItemsJS = require('itemsjs');

const data = [{
  id: 1,
  title: 'Moby Dick',
  text: 'Call me Ishmael. Some years ago...',
  category: 'fiction'
},
{
  id: 2,
  title: 'Zen and the Art of Motorcycle Maintenance',
  text: 'I can see by my watch...',
  category: 'fiction'
},
{
  id: 3,
  title: 'Neuromancer',
  text: 'The sky above the port was...',
  category: 'fiction'
},
{
  id: 4,
  title: 'Zen and the Art of Archery',
  text: 'At first sight it must seem...',
  category: 'non-fiction'
}];

// configuration for itemsjs faceted search
const configuration = {
  native_search_enabled: false,
  aggregations: {
    category: {
      title: 'Categories',
      size: 10,
      conjunction: true
    }
  }
}

// indexing lunr with data
const idx = lunr(function () {
  this.ref('id');
  this.field('title');
  this.field('text');
  this.field('category');

  data.forEach(v => {
    this.add(v);
  });
});

// indexing data into itemsjs
const itemsjs = ItemsJS(data, configuration);

// searching
const search_result = idx.search('sky');
console.log(search_result);

const result = itemsjs.search({
  per_page: 3,
  // important! providing ids from full text search
  ids: search_result.map(v => v.ref),
  filters: {
    category: ['fiction'],
  }
});

console.log(result);
//console.log(result.data.items);
//console.log(result.data.aggregations.category);
```