K
Kyselyā€¢2y ago
Swap

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 šŸ™‚ Note: I am using Postgres.
Solution:
Something like this: ```ts class UpdatedAtPlugin implements KyselyPlugin { transformQuery(args: PluginTransformQueryArgs): RootOperationNode {...
Jump to solution
7 Replies
Swap
SwapOPā€¢2y 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 Ā { kind: "ValueNode"; value: string; }Ā  is not assignable to type Ā OperationNodeĀ 
Object literal may only specify known properties, and Ā valueĀ  does not exist in type Ā OperationNodeĀ 
column-update-node.d.ts(6, 14): The expected type comes from property Ā valueĀ  which is declared here on type Ā ColumnUpdateNode
TS2322: Type Ā { kind: "ValueNode"; value: string; }Ā  is not assignable to type Ā OperationNodeĀ 
Object literal may only specify known properties, and Ā valueĀ  does not exist in type Ā OperationNodeĀ 
column-update-node.d.ts(6, 14): The expected type comes from property Ā valueĀ  which is declared here on type Ā ColumnUpdateNode
Solution
koskimas
koskimasā€¢2y 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
koskimasā€¢2y 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 šŸ˜… Instead consider having another layer on top of Kysely that handles stuff like this.
Swap
SwapOPā€¢2y ago
Absolutely, I agree šŸ˜„ What will your recommendation be for separating this functionality be? I can go with the DB triggers but they also cause performance issues.
koskimas
koskimasā€¢2y 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(),
  })
}
Swap
SwapOPā€¢2y ago
Thanks šŸ™‚
Unknown User
Unknown Userā€¢3d ago
Message Not Public
Sign In & Join Server To View

Did you find this page helpful?