https://github.com/alkemist/compare-engine

Json comparison engine
https://github.com/alkemist/compare-engine

compare diff difference engine json object typescript

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Json comparison engine

• Host: GitHub
• URL: https://github.com/alkemist/compare-engine
• Owner: alkemist
• License: apache-2.0
• Created: 2023-05-29T14:57:38.000Z (almost 3 years ago)
• Default Branch: main
• Last Pushed: 2024-06-12T14:22:44.000Z (almost 2 years ago)
• Last Synced: 2025-05-21T05:13:19.384Z (about 1 year ago)
• Topics: compare, diff, difference, engine, json, object, typescript
• Language: TypeScript
• Homepage:
• Size: 634 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Compare Engine

## Installation

* From npm: `npm install @alkemist/compare-engine`

* From yarn: `yarn add @alkemist/compare-engine`

## Test

* From npm: `npm test`

* From yarn: `yarn test`

## About

Compares 2 value, considering array object movement :

- Either with a signature (identical object)

- Or with a key defined by the method passed to the constructor

- The search is recursive: if an object has been moved within a moved object, it will be detected as moved

- Takes into consideration : value type/class, function name and signature (without parameter type)

## Examples

### With JSON

    import {CompareEngine} from '@alkemist/compare-engine';

    const jsonLeft = {

        objectArray: [

            {

                id: "movedIndex",

                property: "old property",

                otherObjectArray: [

                    {id: "1"},

                    {id: "2"},

                ],

                otherArray: [

                    0, 1, 2

                ]

            },

            {

                id: "removedObject",

            },

            {

                id: "equal"

            }

        ]

    };

    const jsonright = {

        objectArray: [

            {

                id: "newObject",

            },

            {

                id: "movedIndex",

                property: "updated property",

                otherObjectArray: [

                    {id: "2"},

                    {id: "1"},

                ],

                otherArray: [

                    2, 1, 3

                ]

            },

            {

                id: "equal"

            }

        ]

    };

    const compareEngine = new CompareEngine((paths: string[]) => {

      return "id";

    });

    compareEngine.updateLeft(jsonLeft);

    compareEngine.updateRight(jsonRight);

    compareEngine.updateCompareIndex();

    compareEngine.getLeftState("") // return UPDATED CompareState

    compareEngine.getLeftState("objectArray") // return UPDATED CompareState

    compareEngine.getLeftState("objectArray[0]") // return UPDATED CompareState

    compareEngine.getLeftState("objectArray[0].id") // return EQUAL CompareState

    compareEngine.getLeftState("objectArray[0].property") // return UPDATED CompareState

    compareEngine.getLeftState("objectArray[0].otherObjectArray") // return UPDATED CompareState

    compareEngine.getLeftState("objectArray[0].otherObjectArray[0]") // return MOVED CompareState

    compareEngine.getLeftState("objectArray[0].otherObjectArray[0].id") // return NONE CompareState

    compareEngine.getLeftState("objectArray[0].otherObjectArray[1]") // return MOVED CompareState

    compareEngine.getLeftState("objectArray[0].otherObjectArray[1].id") // return NONE CompareState

    compareEngine.getLeftState("objectArray[0].otherArray") // return UPDATED CompareState

    compareEngine.getLeftState("objectArray[0].otherArray[0]") // return REMOVED CompareState

    compareEngine.getLeftState("objectArray[0].otherArray[1]") // return EQUAL CompareState

    compareEngine.getLeftState("objectArray[0].otherArray[2]") // return MOVED CompareState

    compareEngine.getLeftState("objectArray[1]") // return REMOVED CompareState

    compareEngine.getLeftState("objectArray[1].id") // return NONE CompareState

    compareEngine.getLeftState("objectArray[2]") // return EQUAL CompareState

    compareEngine.getLeftState("objectArray[2].id") // return NONE CompareState

    compareEngine.getRightState("") // return UPDATED CompareState

    compareEngine.getRightState("objectArray") // return UPDATED CompareState

    compareEngine.getRightState("objectArray[0]") // return ADDED CompareState

    compareEngine.getRightState("objectArray[0].id") // return NONE CompareState

    compareEngine.getRightState("objectArray[1]") // return UPDATED CompareState

    compareEngine.getRightState("objectArray[1].id") // return EQUAL CompareState

    compareEngine.getRightState("objectArray[1].property") // return UPDATED CompareState

    compareEngine.getRightState("objectArray[1].otherObjectArray") // return UPDATED CompareState

    compareEngine.getRightState("objectArray[1].otherObjectArray[0]") // return MOVED CompareState

    compareEngine.getRightState("objectArray[1].otherObjectArray[0].id") // return NONE CompareState

    compareEngine.getRightState("objectArray[1].otherObjectArray[1]") // return MOVED CompareState

    compareEngine.getRightState("objectArray[1].otherObjectArray[1].id") // return NONE CompareState

    compareEngine.getRightState("objectArray[1].otherArray") // return UPDATED CompareState

    compareEngine.getRightState("objectArray[1].otherArray[0]") // return MOVED CompareState

    compareEngine.getRightState("objectArray[1].otherArray[1]") // return EQUAL CompareState

    compareEngine.getRightState("objectArray[1].otherArray[2]") // return ADDED CompareState

    compareEngine.getRightState("objectArray[2]") // return EQUAL CompareState

    compareEngine.getRightState("objectArray[2].id") // return NONE CompareState

### With Objects

    class Parent {

        constructor(protected property = "value") {

        }

    }

    class Child extends Parent {

        constructor(protected override property = "value") {

            super();

        }

    }

    const compareEngine = new CompareEngine((paths: string[]) => {

      return "id";

    }, new Parent(), new Parent());

    compareEngine.updateCompareIndex();

    compareEngine.getLeftState("") // return EQUAL CompareState

    const compareEngine = new CompareEngine((paths: string[]) => {

      return "id";

    }, new Parent(), new Child());

    compareEngine.updateCompareIndex();

    compareEngine.getLeftState("") // return UPDATED CompareState

    const compareEngine = new CompareEngine((paths: string[]) => {

      return "id";

    }, new Child(), new Child("otherValue"));

    compareEngine.updateCompareIndex();

    compareEngine.getLeftState("") // return UPDATED CompareState

## Exposed models, enums and utils

    enum CompareStateEnum {

        NONE = "",

        ADDED = "added",

        MOVED = "moved",

        UPDATED = "updated",

        REMOVED = "removed",

        EQUAL = "equal",

    }

    class CompareEngine {

        constructor(

            protected determineArrayIndexFn?: (paths: ValueKey[]) => ValueKey

            leftValue?: DATA_TYPE = null,

            rightValue?: DATA_TYPE = null

        )

        get leftValue(): DATA_TYPE | undefined

        get rightValue(): DATA_TYPE | undefined

        getInLeft(paths: ValueKey[] | ValueKey): unknown

        getInRight(paths: ValueKey[] | ValueKey): unknown

        updateLeft(value: DATA_TYPE | undefined): void

        updateRight(value: DATA_TYPE | undefined): void

        updateInLeft(value: DATA_TYPE | undefined, paths: ValueKey[] | ValueKey): void

        updateInRight(value: DATA_TYPE | undefined, paths: ValueKey[] | ValueKey): void

        leftToRight(): void

        rightToLeft(): void

        updateCompareIndex(): void

        hasChange(): boolean

        getLeftState(paths: ValueKey[] | ValueKey): CompareState

        getRightState(paths: ValueKey[] | ValueKey): CompareState

    }

    class CompareState {

        value: CompareStateEnum

        isNone(): boolean

        isAdded(): boolean

        isMoved(): boolean

        isUpdated(): boolean

        isRemoved(): boolean

        isEqual(): boolean

        isChanged(): boolean

        toString(): string

    }

## License

[Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0.html)