codelist-diff

Library for diffing CodeList tables which are defined like this:

interface CodeItem {
    code: number | string;
    category: string;
}

type CodeList = CodeItem[];

Each code-value must be unique within a CodeList.

Install

Install the current version (and save it as a dependency):

$ npm install codelist-diff --save

Usage

const CodelistDiff = require("codelist-diff");

const arr1 = [    
    {
        code: 2,
        category: "Category 2"
    },
    {
        code: 1,
        category: "Category 1"
    }
]

const arr2 = [
    {
        code: 1,
        category: "Category 1"
    },
    {
        code: 2,
        category: "Category 2"
    }
    {
        code: 3,
        category: "Category 2"
    }
]

const delta = CodeListDiff.diff(arr1, arr2);

const arr = CodeListDiff.patch(arr1, delta); // arr is now equal to arr2

It is also possible to add a metadata prop as the 3rd parameter to the diff function. The metadata object will be part of the error thrown if duplicate code-values are detected.

interface Metadata {
    prev: {
        name: string;
        index: number;
    },
    current: {
        name: string;
        index: number;
    }
}

export function diff(prev: CodeItem[], current: CodeItem[], metadata?: Metadata): Delta

export function patch(prev: CodeItem[], delta: Delta)

The format of the delta object returned by the diff function

// Operations should be performed in the order shown in this interface
export interface Delta {
    /**
     * Remove items at these index positions
     */
    remove: number[];
    /**
     * For each index position replace the value with the specified CodeItem
     */
    replace: { [index: number]: CodeItem };
    /**
     * Reorder by replacing values. Every 2 items are a pair: [v1a, v1b, v2a, v2b, ...]
     * v1a: The index in the current array that needs to be replaced
     * v1b: The index in the unmodified prev array to get the new item from
     */
    reorder: number[];
    /**
     * For each index position the specified CodeItem should be inserted
     */
    insert: { [index: number]: CodeItem };
}