170 lines
4.1 KiB
TypeScript
170 lines
4.1 KiB
TypeScript
/**
|
|
* A delta
|
|
*
|
|
* Copyright (C) 2010-2019 R-T Specialty, LLC.
|
|
*
|
|
* This file is part of the Liza Data Collection Framework.
|
|
*
|
|
* liza is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU Affero General Public License as
|
|
* published by the Free Software Foundation, either version 3 of the
|
|
* License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
/** The data structure expected for a document's internal key/value store */
|
|
export type Kv<T = any> = Record<string, T[]>;
|
|
|
|
/** Possible delta values for Kv array indexes */
|
|
export type DeltaDatum<T> = T | null | undefined;
|
|
|
|
|
|
/**
|
|
* The constructor type for a delta generating function
|
|
*
|
|
* @param src - the source data set
|
|
* @param dest - the destination data set
|
|
*
|
|
* @return the delta which transforms src to dest
|
|
*/
|
|
export type DeltaConstructor<T = any, U extends Kv<T> = Kv<T>, V extends Kv<T> = U> = (
|
|
src: U,
|
|
dest: V,
|
|
) => DeltaResult<U & V>;
|
|
|
|
|
|
/** Transform type T to hold possible delta values */
|
|
export type DeltaResult<T> = { [K in keyof T]: DeltaDatum<T[K]> | null };
|
|
|
|
|
|
/**
|
|
* Create delta to transform from src into dest
|
|
*
|
|
* @param src - the source data set
|
|
* @param dest - the destination data set
|
|
*
|
|
* @return the delta
|
|
*/
|
|
export function createDelta<T, U extends Kv<T>, V extends Kv<T>>(
|
|
src: U,
|
|
dest: V,
|
|
): DeltaResult<U & V>
|
|
{
|
|
const delta: DeltaResult<any> = {};
|
|
|
|
// Loop through all keys
|
|
const key_set = new Set(
|
|
Object.keys( src ).concat( Object.keys( dest ) ) );
|
|
|
|
key_set.forEach( key =>
|
|
{
|
|
const src_data = src[ key ];
|
|
const dest_data = dest[ key ];
|
|
|
|
// If source does not contain the key, use entire dest data
|
|
if ( !src_data || !src_data.length )
|
|
{
|
|
delta[ key ] = dest_data;
|
|
|
|
return;
|
|
}
|
|
|
|
// If the key no longer exists in dest then nullify this key
|
|
if ( !dest_data || !dest_data.length )
|
|
{
|
|
delta[ key ] = null;
|
|
|
|
return;
|
|
}
|
|
|
|
// If neither condition above is true then create the key iteratively
|
|
const delta_key = _createDeltaKey( src_data, dest_data );
|
|
|
|
if ( delta_key.changed )
|
|
{
|
|
delta[ key ] = delta_key.data;
|
|
}
|
|
} );
|
|
|
|
return <DeltaResult<U & V>>delta;
|
|
}
|
|
|
|
|
|
/**
|
|
* Build the delta key iteratively
|
|
*
|
|
* @param src - the source data array
|
|
* @param dest - the destination data array
|
|
*
|
|
* @return an object with an identical flag and a data array
|
|
*/
|
|
function _createDeltaKey<T>(
|
|
src: T[],
|
|
dest: T[],
|
|
): { changed: boolean, data: DeltaDatum<T>[] }
|
|
{
|
|
const data = [];
|
|
const max_size = Math.max( dest.length, src.length );
|
|
|
|
let changed: boolean = false;
|
|
|
|
for ( let i = 0; i < max_size; i++ )
|
|
{
|
|
const dest_datum = dest[ i ];
|
|
const src_datum = src[ i ];
|
|
|
|
// terminate the key if we don't have a dest value
|
|
if ( dest_datum === undefined )
|
|
{
|
|
changed = true;
|
|
data[ i ] = null;
|
|
|
|
break;
|
|
}
|
|
else if ( _deepEqual( dest_datum, src_datum ) )
|
|
{
|
|
data[ i ] = undefined;
|
|
}
|
|
else
|
|
{
|
|
changed = true;
|
|
data[ i ] = dest_datum;
|
|
}
|
|
}
|
|
|
|
return {
|
|
changed: changed,
|
|
data: data,
|
|
};
|
|
}
|
|
|
|
|
|
/**
|
|
* Compare two arrays by index
|
|
*
|
|
* @param a - the first array to compare
|
|
* @param b - the second array to compare
|
|
*/
|
|
function _deepEqual( a: any, b: any ): boolean
|
|
{
|
|
if ( Array.isArray( a ) )
|
|
{
|
|
if ( !Array.isArray( b ) || ( a.length !== b.length ) )
|
|
{
|
|
return false;
|
|
}
|
|
|
|
return a.map( ( item, i ) => _deepEqual( item, b[ i ] ) )
|
|
.every( res => res === true );
|
|
}
|
|
|
|
return ''+a === ''+b;
|
|
}
|