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thmsobrmlr/transaction.test.ts

Created June 6, 2021 22:10
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  1. thmsobrmlr created this gist Jun 6, 2021.
    173 changes: 173 additions & 0 deletions transaction.test.ts
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    import mongoose from "mongoose";
    import { prop as Property, getModelForClass } from "@typegoose/typegoose";

    import { withTransaction } from "./transaction";

    class Foo {
    @Property({ required: true })
    example!: string;
    }
    const FooModel = getModelForClass(Foo);

    class Bar {
    @Property({ required: true })
    example!: string;
    }
    const BarModel = getModelForClass(Bar);

    describe("withTransaction", () => {
    beforeEach(async () => {
    await FooModel.createCollection();
    await BarModel.createCollection();
    });

    it("does not roll back changes when not used", async () => {
    const fn = async () => {
    await FooModel.create([{ example: "foo" }]);
    throw new Error();
    };

    await expect(fn).rejects.toThrow();

    expect(await FooModel.countDocuments({})).toBe(1);
    });

    describe("with single model", () => {
    it("rolls back changes when encountering error", async () => {
    const fn = async (session: mongoose.ClientSession) => {
    await FooModel.create([{ example: "foo" }], { session });
    throw new Error();
    };

    await expect(withTransaction(fn)).rejects.toThrow();

    expect(await FooModel.countDocuments({})).toBe(0);
    });

    it("resets mongoose documents when encountering error", async () => {
    const doc = await FooModel.create({ example: "foo" });

    const fn = async (session: mongoose.ClientSession) => {
    doc.example = "new";
    await doc.save({ session });
    throw new Error();
    };

    await expect(withTransaction(fn)).rejects.toThrow();

    expect(doc.modifiedPaths()).toEqual(["example"]);
    });

    it("commits changes without error", async () => {
    const fn = async (session: mongoose.ClientSession) => {
    await FooModel.create([{ example: "foo" }], { session });
    };

    await withTransaction(fn);

    expect(await FooModel.countDocuments({})).toBe(1);
    });
    });

    describe("with multiple models", () => {
    it("rolls back changes when encountering error", async () => {
    const fn = async (session: mongoose.ClientSession) => {
    await FooModel.create([{ example: "foo" }], { session });
    await BarModel.create([{ example: "bar" }], { session });
    throw new Error();
    };

    await expect(withTransaction(fn)).rejects.toThrow();

    expect(await FooModel.countDocuments({})).toBe(0);
    expect(await BarModel.countDocuments({})).toBe(0);
    });

    it("commits changes without error", async () => {
    const fn = async (session: mongoose.ClientSession) => {
    await FooModel.create([{ example: "foo" }], { session });
    await BarModel.create([{ example: "bar" }], { session });
    };

    await withTransaction(fn);

    expect(await FooModel.countDocuments({})).toBe(1);
    expect(await BarModel.countDocuments({})).toBe(1);
    });
    });

    describe("with nested transactions", () => {
    it("rolls back changes when encountering error", async () => {
    const fnFoo = async (existingSession?: mongoose.ClientSession) => {
    await withTransaction(async (session) => {
    await FooModel.create([{ example: "foo" }], { session });
    }, existingSession);
    };
    const fnBar = async (existingSession?: mongoose.ClientSession) => {
    await withTransaction(async (session) => {
    await BarModel.create([{ example: "bar" }], { session });
    throw new Error();
    }, existingSession);
    };
    const fn = async (session: mongoose.ClientSession) => {
    await fnFoo(session);
    await fnBar(session);
    };

    await expect(withTransaction(fn)).rejects.toThrow();

    expect(await FooModel.countDocuments({})).toBe(0);
    expect(await BarModel.countDocuments({})).toBe(0);
    });

    it("resets mongoose documents when encountering error", async () => {
    const foo = await FooModel.create({ example: "foo" });
    const bar = await BarModel.create({ example: "bar" });

    const fnFoo = async (existingSession?: mongoose.ClientSession) => {
    await withTransaction(async (session) => {
    foo.example = "new";
    await foo.save({ session });
    }, existingSession);
    };
    const fnBar = async (existingSession?: mongoose.ClientSession) => {
    await withTransaction(async (session) => {
    bar.example = "new";
    await bar.save({ session });
    throw new Error();
    }, existingSession);
    };
    const fn = async (session: mongoose.ClientSession) => {
    await fnFoo(session);
    await fnBar(session);
    };

    await expect(withTransaction(fn)).rejects.toThrow();

    expect(foo.modifiedPaths()).toEqual(["example"]);
    expect(bar.modifiedPaths()).toEqual(["example"]);
    });

    it("commits changes without error", async () => {
    const fnFoo = async (existingSession?: mongoose.ClientSession) => {
    await withTransaction(async (session) => {
    await FooModel.create([{ example: "foo" }], { session });
    }, existingSession);
    };
    const fnBar = async (existingSession?: mongoose.ClientSession) => {
    await withTransaction(async (session) => {
    await BarModel.create([{ example: "bar" }], { session });
    }, existingSession);
    };
    const fn = async (session: mongoose.ClientSession) => {
    await fnFoo(session);
    await fnBar(session);
    };

    await withTransaction(fn);

    expect(await FooModel.countDocuments({})).toBe(1);
    expect(await BarModel.countDocuments({})).toBe(1);
    });
    });
    });
    24 changes: 24 additions & 0 deletions transaction.ts
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    import mongoose from "mongoose";

    /*
    * See https://github.com/typegoose/typegoose/issues/279#issuecomment-645368737 and
    * https://thecodebarbarian.com/whats-new-in-mongoose-5-10-improved-transactions.html.
    */
    export async function withTransaction(
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    fn: (session: mongoose.ClientSession) => Promise<any>,
    existingSession?: mongoose.ClientSession
    ): Promise<void> {
    if (existingSession) {
    if (existingSession.inTransaction()) return fn(existingSession);

    return mongoose.connection.transaction(fn);
    }

    const session = await mongoose.startSession();
    try {
    await mongoose.connection.transaction(fn);
    } finally {
    session.endSession();
    }
    }