Skip to content

Instantly share code, notes, and snippets.

@busypeoples

busypeoples/diff.js

Last active February 28, 2020 07:35
Show Gist options

  • Select an option

    Learn more about clone URLs
  • Save busypeoples/b4a5513c50b8a235389a145bf23d2815 to your computer and use it in GitHub Desktop.

Select an option

Learn more about clone URLs
Save busypeoples/b4a5513c50b8a235389a145bf23d2815 to your computer and use it in GitHub Desktop.
Download ZIP

Revisions

  1. busypeoples revised this gist Nov 16, 2018. 1 changed file with 2 additions and 2 deletions.
    4 changes: 2 additions & 2 deletions diff.js
    View file
    Original file line number Diff line number Diff line change
    @@ -10,8 +10,8 @@ const diff = (nextItems, currentItems, key, diffFn) => {
    );
    const toUpdate = filter(item => {
    const currentItem = find(propEq(key, item[key]), currentItems);
    return diffFn(item, currentItem);
    }, filter(item => findFn(key, item, currentItems), nextItems));
    return currentItem && diffFn(item, currentItem);
    }, nextItems);
    const toDelete = reject(item => findFn(key, item, nextItems), currentItems);

    return { toCreate, toUpdate, toDelete };
  2. busypeoples revised this gist Sep 23, 2018. No changes.
  3. busypeoples created this gist Sep 23, 2018.
    20 changes: 20 additions & 0 deletions diff.js
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,20 @@
    import { find, filter, propEq, reject } from "ramda";

    const findFn = (key, selectedItem, items) =>
    find(item => item[key] === selectedItem[key], items);

    const diff = (nextItems, currentItems, key, diffFn) => {
    const toCreate = reject(
    item => item[key] && findFn(key, item, currentItems),
    nextItems
    );
    const toUpdate = filter(item => {
    const currentItem = find(propEq(key, item[key]), currentItems);
    return diffFn(item, currentItem);
    }, filter(item => findFn(key, item, currentItems), nextItems));
    const toDelete = reject(item => findFn(key, item, nextItems), currentItems);

    return { toCreate, toUpdate, toDelete };
    };

    export default diff;
    52 changes: 52 additions & 0 deletions diff.test.js
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,52 @@
    import { deepEqual } from "assert";
    import diff from "./index";

    const key = "testId";
    const diffFn = (a, b) => a.name !== b.name;

    const item1 = { testId: 1, name: "First Item" };
    const item2 = { testId: 2, name: "Second Item" };
    const item3 = { testId: 3, name: "Third Item" };
    const item4 = { testId: 4, name: "Fourth Item" };
    const item5 = { testId: 5, name: "Fifth Item" };

    describe("utils/diff", () => {
    it("should return the to be created items", () => {
    const newItem = { name: "New Item" };
    const nextItems = [newItem];
    const previousItems = [item1, item3];
    const { toCreate } = diff(nextItems, previousItems, key, diffFn);
    deepEqual(toCreate, [newItem]);
    });

    it("should return the to be upated items", () => {
    const updatedItem = { testId: 2, name: "UpdatedItem" };
    const nextItems = [item1, updatedItem, item3];
    const previousItems = [item1, item2, item3];
    const { toUpdate } = diff(nextItems, previousItems, key, diffFn);
    deepEqual(toUpdate, [updatedItem]);
    });

    it("should return the to be deleted items", () => {
    const nextItems = [item1, item3];
    const previousItems = [item1, item2, item3];
    const { toDelete } = diff(nextItems, previousItems, key, diffFn);
    deepEqual(toDelete, [item2]);
    });

    it("should return all to be created, updated and deleted items", () => {
    const updatedItem1 = { testId: 1, name: "UpdatedItem1" };
    const updatedItem2 = { testId: 2, name: "UpdatedItem2" };
    const nextItems = [updatedItem1, updatedItem2, item3, item5];
    const previousItems = [item1, item2, item3, item4];
    const { toCreate, toUpdate, toDelete } = diff(
    nextItems,
    previousItems,
    key,
    diffFn
    );
    deepEqual(toCreate, [item5]);
    deepEqual(toUpdate, [updatedItem1, updatedItem2]);
    deepEqual(toDelete, [item4]);
    });
    });