StagingBucket: Do not process non-changes
Since changes trigger any event observers---which can be expensive---it is ideal to ignore sets that do not result in any changes to the bucket. This also resolves issues with systems that are confused by empty diffs. * src/bucket/StagingBucket.js (_hasChanged): Add method. (setValues): Use it. * test/bucket/StagingBucketTest.js: Add test case. DEV-2299master
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@ -161,6 +161,48 @@ module.exports = Class( 'StagingBucket' )
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},
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/**
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* Determine whether values have changed
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*
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* If all values are identical to the current bucket values (relative to
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* `merge_index`), returns `false`. Otherwise, this stops at the first
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* recognized change and returns `true`.
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*
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* @param {Object.<string,Array>} data key/value data or diff
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* @param {boolean} merge_index compare indexes individually
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*
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* @return {boolean} whether a change was recognized
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*/
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'private _hasChanged': function( data, merge_index )
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{
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for ( var name in data )
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{
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var values = data[ name ];
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var cur = this._curdata[ name ] || [];
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if ( !merge_index && ( values.length !== cur.length ) )
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{
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return true;
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}
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for ( var index in values )
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{
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if ( merge_index && ( values[ index ] === undefined ) )
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{
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continue;
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}
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if ( values[ index ] !== cur[ index ] )
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{
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return true;
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}
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}
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}
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return false;
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},
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/**
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* Explicitly sets the contents of the bucket
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*
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@ -174,6 +216,11 @@ module.exports = Class( 'StagingBucket' )
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*/
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'virtual public setValues': function( data, merge_index, merge_null )
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{
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if ( !this._hasChanged( data, merge_index ) )
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{
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return;
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}
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this.emit( this.__self.$('EVENT_STAGING_PRE_UPDATE'), data );
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for ( name in data )
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@ -0,0 +1,185 @@
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/**
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* Test of staging key/value store
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*
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* Copyright (C) 2017 LoVullo Associates, Inc.
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*
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* This file is part of liza.
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*
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* liza is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* @todo This needs tests for the rest of StagingBucket
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*/
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"use strict";
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const { Class } = require( 'easejs' );
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const root = require( '../../' );
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const expect = require( 'chai' ).expect;
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const {
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Bucket,
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StagingBucket: Sut
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} = root.bucket;
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describe( 'StagingBucket', () =>
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{
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describe( 'pre-update event', () =>
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{
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it( 'allows updating data before set', () =>
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{
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const sut = Sut( createStubBucket() );
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const data = {
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foo: [ 'bar', 'baz' ],
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};
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sut.on( 'preStagingUpdate', data =>
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{
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data.foo[ 1 ] = 'quux';
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} );
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// triggers setValues
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sut.setValues( data );
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expect( sut.getDataByName( 'foo' ) )
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.to.deep.equal( [ 'bar', 'quux' ] );
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} );
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[
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ 'bar', 'baz' ] },
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merge_index: true,
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is_change: false,
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},
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ 'bar', 'baz' ] },
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merge_index: false,
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is_change: false,
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},
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// actual changes
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ 'change', 'baz' ] },
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merge_index: true,
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is_change: true,
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},
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ 'bar', 'change' ] },
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merge_index: true,
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is_change: true,
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},
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ undefined, 'change' ] },
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merge_index: true,
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is_change: true,
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},
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// single-index changes make sense only if merge_index
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ undefined, 'baz' ] },
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merge_index: true,
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is_change: false,
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},
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ 'bar', undefined ] },
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merge_index: true,
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is_change: false,
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},
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ 'bar', null ] },
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merge_index: true,
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is_change: true,
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},
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [] },
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merge_index: true,
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is_change: false,
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},
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [] },
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merge_index: false,
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is_change: true,
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},
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{
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initial: { foo: [ 'bar' ] },
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update: { foo: [ 'bar', undefined ] },
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merge_index: false,
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is_change: true,
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},
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// only interpreted as a diff if merge_index
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: { foo: [ 'bar', undefined ] },
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merge_index: false,
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is_change: true,
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},
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// no index at all
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{
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initial: { foo: [ 'bar', 'baz' ] },
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update: {},
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merge_index: true,
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is_change: false,
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},
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].forEach( ( { initial, update, merge_index, is_change }, i ) =>
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{
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it( `is emitted only when data is changed (${i})`, () =>
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{
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const sut = Sut( createStubBucket() );
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let called = false;
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sut.setValues( initial, merge_index );
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sut.on( 'preStagingUpdate', () => called = true );
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sut.setValues( update, merge_index );
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expect( called ).to.equal( is_change );
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} );
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} );
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} );
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} );
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function createStubBucket( bucket_obj )
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{
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return Class.implement( Bucket ).extend(
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{
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'public getData'()
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{
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return bucket_obj;
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},
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'public setValues'( data, merge_index, merge_null ) {},
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'public overwriteValues'( data ) {},
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'public clear'() {},
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'public each'( callback ) {},
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'public getDataByName'( name ) {},
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'public getDataJson'() {},
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'public filter'( pred, callback) {},
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'on'() {},
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} )();
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}
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