js-orm-lib

library1.0.9jsnpmunverified

js-orm-lib v1.0.9 is a lightweight JavaScript ORM library focused on mapping backend API responses to front-end data models and vice versa. It uses a simple mapping configuration with string paths and custom transformation functions. Key differentiators: supports nested field mapping, entity name wrapping for reverse mapping, and requires explicit transformForApi when using functional mappings to ensure data integrity. Release cadence is low; this is the latest stable version. No notable alternatives with the same simplicity.

storage

npm install js-orm-lib

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · JS-ORM-LIB

js-orm-lib

storagejavascriptv1.0.9

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

mapFieldsFromApi

✓ import { mapFieldsFromApi } from 'js-orm-lib'

✗ const mapFieldsFromApi = require('js-orm-lib').mapFieldsFromApi

ESM import only. The package does not export a default; use named imports.

mapFieldsForApi

✓ import { mapFieldsForApi } from 'js-orm-lib'

✗ import mapFieldsForApi from 'js-orm-lib'

Named export, not default.

mapFieldsFromApi and mapFieldsForApi

✓ import { mapFieldsFromApi, mapFieldsForApi } from 'js-orm-lib'

✗ const jsOrm = require('js-orm-lib'); const mapFieldsFromApi = jsOrm.mapFieldsFromApi;

Both functions are named exports; no default export.

Demonstrates basic usage: mapping from API data to frontend model with string paths, function fields, transforms, and reverse mapping.

import { mapFieldsFromApi, mapFieldsForApi } from 'js-orm-lib'; const mockAPIData = { data: { fullName: 'Homer Simpson', ageNumber: 40, location: { town: 'SpringField' } }, favoriteFood: ['beer', 'pizza', 'burger'] }; const mapping = { name: 'data.fullName', age: 'data.ageNumber', homeTown: 'data.location.town', likedFood: 'favoriteFood', firstName: (mappedData, response) => response.data.fullName.split(' ')[0], birthYear: (mappedData, response) => { const date = new Date(); date.setFullYear(date.getFullYear() - mappedData.age); return date.getFullYear(); }, transformFromApi: (mappedData, response) => ({ ...mappedData, beersPerDay: 1, }), transformForApi: (mappedData) => ({ ...mappedData, needsMoreBeer: true, }), }; const mappedResult = mapFieldsFromApi(mockAPIData, mapping); console.log(mappedResult); // Reverse mapping const reversed = mapFieldsForApi(mappedResult, mapping); console.log(reversed);

Debug

Known issues

gotchaIf you use function values or transformFromApi, you must also provide transformForApi, otherwise the library throws an error.

fix

Always include transformForApi when using functional mappings or transformFromApi.

affects: >=0.0.0

gotchastring path mappings are reversed when calling mapFieldsForApi, but function fields and transformFromApi fields persist as-is.

fix

Be aware that only string paths are reversed; custom logic must be handled in transformForApi.

affects: >=0.0.0

gotchaThe library does not support async transformation functions. Functions must be synchronous.

fix

Do not use async/await in mapping functions; preprocess data before mapping if asynchronous operations are needed.

affects: >=0.0.0

Errors

Common errors & fixes

TypeError: Cannot read properties of undefined (reading 'split')

Mapping function accesses a property on response that doesn't exist or is undefined.

fix

Ensure the response object contains the expected nested property before accessing it. Use optional chaining or check existence.

Error: You need to specify a `transformForApi` function in the mapping because you used a function field or `transformFromApi` option.

Used function value or transformFromApi without providing transformForApi.

fix

Add transformForApi to the mapping configuration.

TypeError: mapping is not a valid object

Passed null, undefined, or non-object as mapping parameter.

fix

Ensure mapping is a plain object with string keys and string/function values.

Upgrade

Version history

1.0.9latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

25 hits · last 30 days

node

Resources

githubhttps://github.com/matesk8/js-orm ↗

packagejs-orm-lib ↗

homepagehttps://github.com/matesk8/js-orm#readme ↗