Kysely•16mo ago

Plugin for auto-update "updated_at" field

Hello Team, Greetings! I am trying to write a plugin that will auto-update the "updated_at" column when there will be an update operation. So far, I have implemented the following code:

export class SetUpdatedAtTransformer extends OperationNodeTransformer {

    protected transformUpdateQuery(node: UpdateQueryNode): UpdateQueryNode {
        return this.#transformQuery(super.transformUpdateQuery(node));
    }

    #transformQuery<T extends UpdateQueryNode>(node: T): T {
        if (!node.updates || node.updates.length === 0) {
            return node;
        }

        return freeze({
            ...node,
            updates: this.#setUpdatedAt(node.updates),
        });
    }

    #setUpdatedAt(updates: ReadonlyArray<ColumnUpdateNode>): ReadonlyArray<ColumnUpdateNode> {
        const out: ColumnUpdateNode[] = [];
        out.push(...updates);

        return freeze(out);
    }
}

export class SetUpdatedAtTransformer extends OperationNodeTransformer {

    protected transformUpdateQuery(node: UpdateQueryNode): UpdateQueryNode {
        return this.#transformQuery(super.transformUpdateQuery(node));
    }

    #transformQuery<T extends UpdateQueryNode>(node: T): T {
        if (!node.updates || node.updates.length === 0) {
            return node;
        }

        return freeze({
            ...node,
            updates: this.#setUpdatedAt(node.updates),
        });
    }

    #setUpdatedAt(updates: ReadonlyArray<ColumnUpdateNode>): ReadonlyArray<ColumnUpdateNode> {
        const out: ColumnUpdateNode[] = [];
        out.push(...updates);

        return freeze(out);
    }
}

export class UpdatedAtPlugin implements KyselyPlugin {
    readonly #transformer = new SetUpdatedAtTransformer();

    transformQuery(args: PluginTransformQueryArgs): RootOperationNode {
        return this.#transformer.transformNode(args.node);
    }

transformResult(
        args: PluginTransformResultArgs
    ): Promise<QueryResult<UnknownRow>> {
        return Promise.resolve(args.result);
    }
}

export class UpdatedAtPlugin implements KyselyPlugin {
    readonly #transformer = new SetUpdatedAtTransformer();

    transformQuery(args: PluginTransformQueryArgs): RootOperationNode {
        return this.#transformer.transformNode(args.node);
    }

transformResult(
        args: PluginTransformResultArgs
    ): Promise<QueryResult<UnknownRow>> {
        return Promise.resolve(args.result);
    }
}

But not sure how to implement further for auto-updating the column, any help or suggestion will really helpful. Thanks 🙂 Note: I am using Postgres.

Solution:

Something like this: ```ts class UpdatedAtPlugin implements KyselyPlugin { transformQuery(args: PluginTransformQueryArgs): RootOperationNode {...

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6 Replies

SwapOP•16mo ago

Going further, i have removed SetUpdatedAtTransformer class and my modified plugin is follows:

export class UpdatedAtPlugin implements KyselyPlugin {

    transformQuery(args: PluginTransformQueryArgs): RootOperationNode {
        if (args.node.kind === "UpdateQueryNode") {
            const arr: ColumnUpdateNode[] = [];

            arr.push(...args.node.updates);
            arr.push(
                {
                    kind: 'ColumnUpdateNode',
                    column: {
                        kind: 'ColumnNode',
                        column: { kind: 'IdentifierNode', name: 'updated_at' }
                    },
                    value: { kind: 'ValueNode', value: '${new Date()}' }
                }
            );

            return {
                ...args.node,
                updates: arr,
            };
        }

        return args.node;
    }

    transformResult(
        args: PluginTransformResultArgs
    ): Promise<QueryResult<UnknownRow>> {
        return Promise.resolve(args.result);
    }
}

export class UpdatedAtPlugin implements KyselyPlugin {

    transformQuery(args: PluginTransformQueryArgs): RootOperationNode {
        if (args.node.kind === "UpdateQueryNode") {
            const arr: ColumnUpdateNode[] = [];

            arr.push(...args.node.updates);
            arr.push(
                {
                    kind: 'ColumnUpdateNode',
                    column: {
                        kind: 'ColumnNode',
                        column: { kind: 'IdentifierNode', name: 'updated_at' }
                    },
                    value: { kind: 'ValueNode', value: '${new Date()}' }
                }
            );

            return {
                ...args.node,
                updates: arr,
            };
        }

        return args.node;
    }

    transformResult(
        args: PluginTransformResultArgs
    ): Promise<QueryResult<UnknownRow>> {
        return Promise.resolve(args.result);
    }
}

But, getting type error

TS2322: Type  { kind: "ValueNode"; value: string; }  is not assignable to type  OperationNode 
Object literal may only specify known properties, and  value  does not exist in type  OperationNode 
column-update-node.d.ts(6, 14): The expected type comes from property  value  which is declared here on type  ColumnUpdateNode

TS2322: Type  { kind: "ValueNode"; value: string; }  is not assignable to type  OperationNode 
Object literal may only specify known properties, and  value  does not exist in type  OperationNode 
column-update-node.d.ts(6, 14): The expected type comes from property  value  which is declared here on type  ColumnUpdateNode

Solution

koskimas•16mo ago

Something like this:

class UpdatedAtPlugin implements KyselyPlugin {
  transformQuery(args: PluginTransformQueryArgs): RootOperationNode {
    if (args.node.kind === "UpdateQueryNode") {
      const arr: ColumnUpdateNode[] = [];

      arr.push(...args.node.updates!);
      arr.push(ColumnUpdateNode.create(
        ColumnNode.create("updated_at"),
        ValueNode.create(new Date().toISOString())
      ));

      return {
        ...args.node,
        updates: arr,
      };
    }

    return args.node;
  }

  transformResult(
    args: PluginTransformResultArgs
  ): Promise<QueryResult<UnknownRow>> {
    return Promise.resolve(args.result);
  }
}

class UpdatedAtPlugin implements KyselyPlugin {
  transformQuery(args: PluginTransformQueryArgs): RootOperationNode {
    if (args.node.kind === "UpdateQueryNode") {
      const arr: ColumnUpdateNode[] = [];

      arr.push(...args.node.updates!);
      arr.push(ColumnUpdateNode.create(
        ColumnNode.create("updated_at"),
        ValueNode.create(new Date().toISOString())
      ));

      return {
        ...args.node,
        updates: arr,
      };
    }

    return args.node;
  }

  transformResult(
    args: PluginTransformResultArgs
  ): Promise<QueryResult<UnknownRow>> {
    return Promise.resolve(args.result);
  }
}

koskimas•16mo ago

But I don't recommend doing things like this inside a query builder. You're trying to turn a query builder into an ORM. You'll end up with a really shitty and unpredictable ORM 😅 Instead consider having another layer on top of Kysely that handles stuff like this.

SwapOP•16mo ago

Absolutely, I agree 😄 What will your recommendation be for separating this functionality be? I can go with the DB triggers but they also cause performance issues.

koskimas•16mo ago

Depends completely on what you like and how you structure your code but at its simplest, just a updatePerson function:

async function updatePerson(person: Updateable<PersonTable>) {
  return await db.updateTable('person').set({
    ...person,
    updated_at: new Date(),
  })
}

async function updatePerson(person: Updateable<PersonTable>) {
  return await db.updateTable('person').set({
    ...person,
    updated_at: new Date(),
  })
}

SwapOP•16mo ago

Thanks 🙂

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Plugin for auto-update "updated_at" field