Column overrides

[gittgott]

This is somewhat related to #34, #75, and #30.

This follows the format in the JSON configuration issue (#34), so it should be adaptable to that. This does not implement any sort of TypeScript parsing. It will simply copy the value of the column name's override as an IdentifierNode. This will at least allow for simple type overrides, but I'm not entirely certain of what will and won't be supported with this.

I was also uncertain if the override in #transformColumn should truly override the type or if it should respect the isNullable or isGenerated parts of that. For now, I just have it as a true override which ignores those.

I have kept this as a property on the Generator class, and it is not included as a CLI option. I was not sure how this would be best implemented, so I left it alone for now and am just making it available through custom scripts.

I'm looking for some feedback on my prior uncertainties and if I'm missing anything glaringly obvious. Thanks!

[RobinBlomberg]

Great start! I looked at the code and it looks quite good. Two comments:

1. I should definitely add an ESLint auto-fix rule for this, but until then, can you keep the properties alphabetically sorted? 😁

2. I don't think we should reuse IdentifierNode for this. I would introduce RawExpressionNode like this (and add it to ExpressionNode and NodeType:

import { NodeType } from './node-type';

export class RawExpressionNode {
  readonly expression: string;
  readonly type = NodeType.RAW_EXPRESSION;

  constructor(expression: string) {
    this.expression = expression;
  }
}

In the future, I guess the Overrides.columns signature will look like Record<string, Node | string>. If it's not an easy fix, we could skip it for now. I appreciate the work!

[gittgott]

I updated the column.overrides to allow for ExpressionNodes instead of just strings. This appears to be working for me with something like the following:

{
  overrides: {
    columns: {
      "<table_name>.<column_name>": new GenericExpressionNode("Generated", [
        new RawExpressionNode("boolean"),
      ]),
    },
  },
};

[RobinBlomberg]

Looks great! I will test this as soon as I have time.

[gittgott]

I have one more fix that I just committed.

I remembered that kysely prefers json columns to be wrapped with the JSONColumnType type which is really just an alias for ColumnType<T, string, string>. This is due to the fact that the data should be a string when updating and inserting to that column, but will come back as JSON when selecting. I added a node just like ColumnType called JSONColumnType to simplify the usage of JSON columns in overrides. I wanted to be able to directly import JSONColumnType from kysely in the generated code, but adding that to GLOBAL_IMPORTS didn't seem to be working - it wasn't including that as an import in the generated file. Because of this, I just am outputting ColumnType<T, string, string> since ColumnType is already imported.

All of this is possible by just using a string override (like { '<column_name>.<table_name>': 'ColumnType<{ postalCode: string; street: string; city: string }>, string, string' }) but I think that that could be a bit confusing to write.

[zhy0216]

is it possible to use this from cli?

[zhy0216]

is it possible to use this from cli?

see pr here: https://github.com/gittgott/kysely-codegen/pull/2

[tylrw]

I have one more fix that I just committed.

I remembered that kysely prefers json columns to be wrapped with the JSONColumnType type which is really just an alias for ColumnType<T, string, string>. This is due to the fact that the data should be a string when updating and inserting to that column, but will come back as JSON when selecting. I added a node just like ColumnType called JSONColumnType to simplify the usage of JSON columns in overrides. I wanted to be able to directly import JSONColumnType from kysely in the generated code, but adding that to GLOBAL_IMPORTS didn't seem to be working - it wasn't including that as an import in the generated file. Because of this, I just am outputting ColumnType<T, string, string> since ColumnType is already imported.

All of this is possible by just using a string override (like { '<column_name>.<table_name>': 'ColumnType<{ postalCode: string; street: string; city: string }>, string, string' }) but I think that that could be a bit confusing to write.

gittgott, I noticed GLOBAL_IMPORTS are not included in the output without a corresponding matching node. When it didn't work for me, I tried to import a TypeScript namespace, Temporal, and utilize with Temporal.PlainDate. Excluded as Temporal != Temporal.PlainDate.

[RobinBlomberg]

Amazing work guys! I implemented both your suggestions and also made the Kysely JSONColumnType work. This will be in the next release as soon as I release it.