An alternative SimpleSchema implementation

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561.0.0-rc14 years ago6 years agoMinified + gzip package size for very-simple-schema in KB


Bundle size: ~22.5 kB, ~5.5 kB gzipped
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Like SimpleSchema but even simpler

This package implements an essential subset of SimpleSchema. Unlike the original version it does not provide validation of Mongo selectors, nor does it allow you to define default and auto values. Despite the limited functionality it may still be an interesting alternative for solving problems like:
  • form validation - it integrates nicely with redux-form
  • function parameters validation, e.g. in remote api calls


npm install --save very-simple-schema

Basic usage

import { Schema } from 'very-simple-schema';

const Book = new Schema({
  author:    { type: String, nonEmpty: true }, // must be present and non-empty
  title:     { type: String, optional: true, nonEmpty: true }, // can be missing, but if present then must be non-empty
  abstract:  { type: String, optional: true }, // can be missing
  signature: { type: String }, // must be present, if present can be empty


Unlkie in SimpleSchema, empty strings are accepted even if a property is required. The reason SimpleSchema treats them differently is that clean method is being called on an object before it's validated. To emulate the original behavior you can create a custom Schema class with different default behavior:
import { createSchema, presetDefault } from 'very-simple-schema';

const Schema = createSchema({
  plugins: [
  emptyStringsAreMissingValues: true,


import { Schema } from 'very-simple-schema';

// a number between 0 and 10
new Schema(Number, { min: 0, max: 10 });

// array with at least element
Schema.arrayOf(Schema.any(), { minCount: 1 });

// object that contains anything

// either Yes or No
Schema.enum(['Yes', 'No']);

// can be one of the specified types
const Id = Schema.oneOf([String, Number]);

const User = new Schema({
  name: { type: String },
  email: { type: String, regEx: Schema.RegEx.Email, optional: true },
}, {
  // custom typeName can improve some error messages
  typeName: 'User',

const Book = new Schema({
  id: { type: Id },
  // type can reference another schema
  author: { type: User },
  // strings can be requested to be non empty
  title: { type: String, nonEmpty: true },
  abstract: { type: String },
  // array can be constructed with [] shortcut, maxCount refers to array lenght, max refers to string length
  chapters: { type: [String], '$.max': 128, maxCount: 10 },
}, { typeName: 'Book' });

const Library = new Schema({
  books: { type: [Book], maxCount: 1000 },
}, {
  typeName: 'Library',