Interface TableSchemaInferenceOverrides

Overview

Provides a way to override the type of specific datatypes in the InferTableSchema-like utility types.

Use-case: Custom ser/des

This is especially useful when working with custom ser/des, requiring you to use a different type for a specific datatype.

Example

const BigIntAsBigNumberCodec = TableCodecs.forType('bigint', {
  deserialize: (value, ctx) => ctx.done(BigNumber(value)),
});

const ProductSchema = Table.schema({
  columns: {
    id: 'bigint',
    description: 'text',
    price: 'bigint',
  },
  primaryKey: 'id',
});

// type Product = {
//   id: BigNumber, (primary key is always non-null)
//   description?: string | null,
//   price?: BigNumber | null,
// }
type Product = InferTableSchema<typeof ProductSchema, { bigint: BigNumber | null }>;

const table = await db.createTable('products', {
  definition: ProductSchema,
  serdes: {
    codecs: [BigIntAsBigNumberCodec],
  },
});
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Use-case: Removing | null

If you really want a column to be non-null, you can use the TypeOverrides type to override the type of a specific datatype to be non-null.

Example

const ProductSchema = Table.schema({
  columns: {
    id: 'bigint',
    description: 'text',
    price: 'bigint',
  },
  primaryKey: 'id',
});

// type Product = {
//   id: BigNumber, (primary key is always non-null)
//   description?: string,
//   price?: BigNumber,
// }
type Product = InferTableSchema<typeof ProductSchema, {
  bigint: BigNumber,
  text: string,
}>;
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Use-case: Adding datatypes

You can also add typing support for a datatype which isn't yet supported by the client.

Example

const ProductSchema = Table.schema({
  columns: {
    id: 'bigint',
    description: 'text',
    price: 'super_duper_bigint',
  },
  primaryKey: 'id',
});

// type Product = {
//   id: BigNumber,
//   description?: string,
//   price?: BigNumber,
// }
type Product = InferTableSchema<typeof ProductSchema, {
  super_duper_bigint: BigNumber,
}>;
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Overriding collection types

🚨Important: Because TypeScript does not natively support higher-kinded types, it is not yet possible to polymorphically override the type of collection types (e.g. list, set, map).

However, you can still technically override the type of a collection datatype monomorphically.

Example

const ExampleSchema = Table.schema({
  columns: {
    id: 'uuid',
    map: { type: 'map', keyType: 'text', valueType: 'int' },
  },
  primaryKey: 'id',
});

// type Example = {
//   id: UUID,
//   map?: Record<string, number>,
// }
type Example = InferTableSchema<typeof ExampleSchema, {
  map: Map<string, number>,
}>;
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