shelving/db/provider/PostgreSQLProvider.js

Toolkit for using data in JavaScript.

import { SQLProvider } from "./SQLProvider.js";
/** Abstract PostgreSQL provider with JSONB function support for nested keys, array containment, and array mutations. */
export class PostgreSQLProvider extends SQLProvider {
    /** Get the Postgres JSONB path for the nested segments of a key, e.g. `{"b","c"}`. */
    sqlPath(key) {
        return this.sqlConcat(key.slice(1).map(k => this.sqlIdentifier(k)), ",", "{", "}");
    }
    /** Get the Postgres JSONB extract syntax, e.g. `"a" #>> {"b","c"}` */
    sqlExtract(key) {
        const column = this.sqlIdentifier(key[0]);
        if (key.length > 1) {
            const path = this.sqlPath(key);
            return this.sql `${column} #>> ${path}`;
        }
        return column;
    }
    // Override to implement `with` and `omit` updates and deeply nested JSONB values.
    sqlUpdate(update) {
        const { action, key, value } = update;
        const column = this.sqlIdentifier(key[0]);
        // Implement all updates for deeply nested paths.
        if (key.length > 1) {
            const path = this.sqlPath(key);
            if (action === "set") {
                return this.sql `${column} = jsonb_set(${column}, ${path}, ${value})`;
            }
            if (action === "sum") {
                return this.sql `${column} = jsonb_set(${column}, ${path}, (${column} #>> ${path}) + ${value})`;
            }
            const source = this.sql `${column} #> ${path}`;
            if (action === "with") {
                return this.sql `${column} = jsonb_set(${column}, ${path}, ${source} || (
					SELECT COALESCE(jsonb_agg(elem), '[]'::jsonb)
					FROM jsonb_array_elements(${value}) AS elem
					WHERE NOT ${source} @> jsonb_build_array(elem)
				), false)`;
            }
            if (action === "omit") {
                return this.sql `${column} = jsonb_set(${column}, ${path}, (
					SELECT COALESCE(jsonb_agg(elem), '[]'::jsonb)
					FROM jsonb_array_elements(${source}) AS elem
					WHERE NOT ${value} @> jsonb_build_array(elem)
				), false)`;
            }
            return action; // Never happens.
        }
        // Implement `with` and `omit` on flat values.
        if (action === "with") {
            return this.sql `${column} = ${column} || (
				SELECT COALESCE(jsonb_agg(elem), '[]'::jsonb)
				FROM jsonb_array_elements(${value}) AS elem
				WHERE NOT ${column} @> jsonb_build_array(elem)
			)`;
        }
        if (action === "omit") {
            return this.sql `${column} = (
				SELECT COALESCE(jsonb_agg(elem), '[]'::jsonb)
				FROM jsonb_array_elements(${column}) AS elem
				WHERE NOT ${value} @> jsonb_build_array(elem)
			)`;
        }
        return super.sqlUpdate(update);
    }
    // Override to implement deeply-nested JSONB queries.
    sqlFilter(filter) {
        const { key, operator, value } = filter;
        // Implement `contains` filters.
        if (operator === "contains")
            return this.sql `${this.sqlExtract(key)} @> ${[value]}`;
        return super.sqlFilter(filter);
    }
}