kysely
Version:
Type safe SQL query builder
108 lines (107 loc) • 3.03 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.ParseJSONResultsPlugin = void 0;
const object_utils_js_1 = require("../../util/object-utils.js");
/**
* Parses JSON strings in query results into JSON objects.
*
* This plugin can be useful with dialects that don't automatically parse
* JSON into objects and arrays but return JSON strings instead.
*
* To apply this plugin globally, pass an instance of it to the `plugins` option
* when creating a new `Kysely` instance:
*
* ```ts
* import * as Sqlite from 'better-sqlite3'
* import { Kysely, ParseJSONResultsPlugin, SqliteDialect } from 'kysely'
* import type { Database } from 'type-editor' // imaginary module
*
* const db = new Kysely<Database>({
* dialect: new SqliteDialect({
* database: new Sqlite(':memory:'),
* }),
* plugins: [new ParseJSONResultsPlugin()],
* })
* ```
*
* To apply this plugin to a single query:
*
* ```ts
* import { ParseJSONResultsPlugin } from 'kysely'
* import { jsonArrayFrom } from 'kysely/helpers/sqlite'
*
* const result = await db
* .selectFrom('person')
* .select((eb) => [
* 'id',
* 'first_name',
* 'last_name',
* jsonArrayFrom(
* eb.selectFrom('pet')
* .whereRef('owner_id', '=', 'person.id')
* .select(['name', 'species'])
* ).as('pets')
* ])
* .withPlugin(new ParseJSONResultsPlugin())
* .execute()
* ```
*/
class ParseJSONResultsPlugin {
opt;
#objectStrategy;
constructor(opt = {}) {
this.opt = opt;
this.#objectStrategy = opt.objectStrategy || 'in-place';
}
// noop
transformQuery(args) {
return args.node;
}
async transformResult(args) {
return {
...args.result,
rows: parseArray(args.result.rows, this.#objectStrategy),
};
}
}
exports.ParseJSONResultsPlugin = ParseJSONResultsPlugin;
function parseArray(arr, objectStrategy) {
const target = objectStrategy === 'create' ? new Array(arr.length) : arr;
for (let i = 0; i < arr.length; ++i) {
target[i] = parse(arr[i], objectStrategy);
}
return target;
}
function parse(obj, objectStrategy) {
if ((0, object_utils_js_1.isString)(obj)) {
return parseString(obj);
}
if (Array.isArray(obj)) {
return parseArray(obj, objectStrategy);
}
if ((0, object_utils_js_1.isPlainObject)(obj)) {
return parseObject(obj, objectStrategy);
}
return obj;
}
function parseString(str) {
if (maybeJson(str)) {
try {
return parse(JSON.parse(str), 'in-place');
}
catch (err) {
// this catch block is intentionally empty.
}
}
return str;
}
function maybeJson(value) {
return value.match(/^[\[\{]/) != null;
}
function parseObject(obj, objectStrategy) {
const target = objectStrategy === 'create' ? {} : obj;
for (const key in obj) {
target[key] = parse(obj[key], objectStrategy);
}
return target;
}