cjs-indexing-hash

lightweight key-value store with support for auto-updating indexes ( indices? you know what i mean ... )

install

npm i cjs-indexing-hash

how to use

create new instance (empty)

var create_indexing_hash = require('cjs-indexing-hash'),
    indexing_hash = create_indexing_hash();

create new instance from existing data

> objects

var users = {
      batman: { is_cool: true },
      superman: { is_cool: false }
    },
    indexable_users = create_indexing_hash( users );

> arrays

var users = [
      { id: batman, is_cool: true },
      { id: superman, is_cool: false }
    ],
    indexable_users = create_indexing_hash( users );

> strings

var indexable_string = create_indexing_hash( 'why would you want to do this? who cares! it works!!!' );

get entry

// from object
var batman = indexable_users.get( 'batman' );

// from array
var batman = indexable_users.get( 0 );

// from string
var y = indexable_string.get( '2' );

add entry

indexable_users.add( 'wonder_woman', { is_cool: true });

create index

indexable_users.add_index( 'is-cool', function( entry, add_to_index ){
  if(  entry.is_cool == true ) add_to_index();
});

get keys in index

var cool_users = indexable_users.index_get( 'is-cool' );

get keys in multiple indexes (indices)

var cool_users_with_capes = indexable_users.intersect_indexes([ 'is-cool', 'has-cape' ]);

hooks

default indexing-hash behavior

written in expected hook execution order

// hook: key-created
//       * executes whenever an item is added to indexing-hash
hooks.add( 'key-created', 'update-collection-keys-cache', ({ key, val }) => {})
hooks.add( 'key-created', 'index-new-entry', ({ key, val }) => {})


// hook: key-deleted
//       * executes whenever an item is removed from indexing-hash
hooks.add( 'key-deleted', 'update-collection-keys-cache', ({ key, val }) => {})
hooks.add( 'key-deleted', 'remove-from-indexes', ({ key, val }) => {})

// hook: key-updated
//       * executes whenever an item in indexing-hash is updated
hooks.add( 'key-updated', 'update-indexes', ({ key, val }) => {})

// hook: index-created
//       * executes whenever an index is added to indexing-hash
hooks.add( 'index-created', 'populate-created-index', ({ name }) => {})

create custom indexing-hash behavior

indexable_users.hooks.add( 'key-created', 'log-user-creation', ({ key, val }) => {
      const user = val
      console.log( `action=user-created id=${ key } cool=${ user.is_cool }` )
})

indexable_users.hooks.add( 'index-created', 'log-index-creation', ({ name }) => {
      console.log( `action=index-created name=${ name }` )
})

indexable_users.hooks.add( 'key-deleted', 'send-user-deletion-email', ({ key, val }) => {
      const user_at_deletion = val
      if (user_at_deletion.email) {
            // send email
            console.log( `action=send-deletion-email user=${ key }` )
      }
})