@sqb/connect/orm/decorators/link.decorator.js

Multi-dialect database connection framework written with TypeScript

import { EntityMetadata } from '../model/entity-metadata.js';
import { LinkChain } from '../model/link-chain.js';
export function Link(options) {
    let root;
    let chain;
    const fn = (target, propertyKey) => {
        if (typeof propertyKey !== 'string')
            throw new TypeError('Symbol properties are not allowed');
        const reflectType = Reflect.getMetadata('design:type', target, propertyKey);
        if (!root) {
            if (reflectType === Array) {
                throw new TypeError(`Can't get type information while it is an array. Please define entity type`);
            }
            if (!EntityMetadata.get(reflectType))
                throw new TypeError(`No entity metadata found for type "${reflectType}"`);
            fn.toOne(reflectType);
        }
        if (reflectType !== Array && root.first.returnsMany()) {
            throw new TypeError(`Link returns single instance however property type is an array`);
        }
        if (reflectType === Array && !root.first.returnsMany()) {
            throw new TypeError(`Link returns array of instances however property type is not an array`);
        }
        const entity = EntityMetadata.define(target.constructor);
        // @ts-ignore
        // noinspection JSConstantReassignment
        root.first.source = entity.ctor;
        EntityMetadata.defineAssociationField(entity, propertyKey, root.first, options);
    };
    fn.toOne = (type, args) => {
        if (chain) {
            chain = chain.linkToOne(type, args?.targetKey, args?.sourceKey);
            if (args?.where)
                chain.where(args.where);
            return fn;
        }
        root = linkToOne(type, args?.targetKey, args?.sourceKey);
        chain = root;
        if (args?.where)
            chain.where(args.where);
        return fn;
    };
    fn.toMany = (type, args) => {
        if (chain) {
            chain = chain.linkToMany(type, args?.targetKey, args?.sourceKey);
            if (args?.where)
                chain.where(args.where);
            return fn;
        }
        root = linkToMany(type, args?.targetKey, args?.sourceKey);
        chain = root;
        if (args?.where)
            chain.where(args.where);
        return fn;
    };
    return fn;
}
/**
 * Crates an Link Chain object
 */
function linkToOne(type, targetKey, sourceKey) {
    return new LinkChain(type, targetKey, sourceKey);
}
/**
 * Crates an Link Chain object
 */
function linkToMany(type, targetKey, sourceKey) {
    return new LinkChain(type, targetKey, sourceKey, true);
}