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    osom

    3.1.2 • Public • Published

    osom

    An Awesome [/osom/] Object Data Modeling. Inspired in mongoose but Database Agnostic.

    Last version Coverage Status NPM Status

    Installation

    $ npm install osom --save

    Preview

    const osom = require('osom')
    
    function trim (str) {
      return str.trim()
    }
    
    function isValidTitle (str) {
      return str.length > 0
    }
    
    // setup your schema
    const schema = {
      title: {
        type: String,
        validate: isValidTitle,
        transform: [trim]
      },
      category: String,
      type: String,
      source: String,
      link: String,
      createdAt: String,
      updatedAt: String
    }
    
    // create validator based on schemas
    const validator = osom(schema)
    
    // validate it!
    validator({ title: '  23  ' }) // => {title: '23'}

    Usage

    osom(schema, [global])

    where:

    • schema: It represents a set of rules (one per each key) that will be used for validate an object.
    • global (optional): It brings you the possibility to declare global rules definition as helper to avoid write repetitive code.

    After that, you will have a validator function that you can invoke passing the object to be validate.

    Schema

    Simple

    The most common use case is validate the type of something.

    If you are only interested in the type, you can provide a simple schema like:

    const simpleSchema = {
      age: Number
    }

    Where key is the name of the rule and value the type of it.

    Advanced

    The basic mode is a simplification of the advanced mode for the most common use case.

    While in basic mode only is possible setup type, in advanced mode you can setup more things providing a configurable object.

    Each key of the object represent a rule . It's possible setup different things in the same rule.

    Defining Rules

    type

    Type: function

    As in basic mode, it specifies the type of the output value:

    const schema = {
      age: {
        type: Number
      }
    }

    Internally it uses chaste. This makes easy casting compatible types:

    const schema = {
      age: {
        type: Number
      }
    }
    
    const validator = osom(schema)
    validator({ age: '23' }) // => {age: 23}

    casting

    Type: boolean
    Default: true

    It enable/disable type casting. An TypeError will be throwed under different type evaluation.

    const schema = {
      age: {
        type: String,
        casting: false
      }
    }
    
    const validator = osom(schema)
    validator({ age: '23' }) // => TypeError("Expected a {string} for 'age'.")

    required

    Type: boolean|string
    Default: false

    It marks a rule as required field and throws TypeError if value for the field is not present.

    Additionally is possible provide a custom error message. For do it, pass an String.

    const schema = {
      age: {
        type: String,
        required: 'sorry but you must provide an age.'
      }
    }
    
    const validator = osom(schema)
    validator({}) // => TypeError("sorry but you must provide an age")

    default

    Type: string|object|number|boolean|function
    Default: null

    It sets a default value if nill value as input is provided.

    Additionally you can provide a function for set a dynamic value:

    const schema = {
      age: {
        type: Number, default: function () { return 23 }
      }
    }
    
    const validator = osom(schema)
    validator({}) // => { age: 23 }

    transform

    Type: function|array
    Default: []

    It transforms the input value.

    The Methods provided in the array are applied as pipeline (the input of the second is the output of the first).

    function trim (str) {
      return str.trim()
    }
    
    const schema = {
      age: {
        type: String,
        transform: [trim]
      }
    }
    
    const validator = osom(schema)
    validator({ age: '    23   ' }) // => { age: '23' }

    validate

    Type: function|object
    Default: null

    It set up a function that will be exec to validate the input value. If it fails, it throws TypeError.

    const schema = {
      age: {
        type: String,
        validate: function (v) {
          return v === '23'
        }
      }
    }
    
    const validator = osom(schema)
    validator({ age: 25 }) // => TypeError("Fail '25' validation for 'age'.")

    Providing a object brings you the possibility set up a custom error message:

    const schema = {
      age: {
        type: String,
        validate: {
          validator: function (v) {
            return v === '23'
          },
          message: 'expected a millenial value instead of %s!'
        }
      }
    }
    
    const validator = osom(schema)
    validator({ age: 25 }) // => TypeError("expected a millenial value instead of 25!")

    Defining Global Rules

    While is possible provide specific setup per each rule, also is possible provide them as global to apply to all rules.

    This minimizes the schemas definitions.

    function trim (str) {
      return str.trim()
    }
    
    const schema = {
      age: {
        type: String
      }
    }
    
    const globalFields = {
      transform: [trim]
    }
    
    const validator = osom(schema, globalFields)
    validator({ age: '  23  ' }) // => {age: '23'}

    No problem if later you need to avoid it for a specific case.

    function trim (str) {
      return str.trim()
    }
    
    const schema = {
      age: {
        type: String,
        transform: []
      }
    }
    
    const globalFields = {
      transform: [trim]
    }
    
    const validator = osom(schema, globalFields)
    validator({ age: '  23  ' }) // => {age: '  23  '}

    Tips

    Working with async code

    This library works synchronously.

    However, you can use it comfortably in a async workflow transforming the interface into a callback/promise style.

    For example, consider use async#asyncify for do it. we could have a schema.js file like:

    const schema = osom({
      title: {
        type: String,
        validate: isValidTitle,
        transform: [trim]
      },
      category: String,
      type: String,
      source: String,
      link: String,
      createdAt: String,
      updatedAt: String
    })
    
    module.exports = async.asyncify(schema)
    module.exports.sync = schema

    Then you only need use it into a async workflow:

    const schema = require('./schema')
    schema(data, function (validationError, instance) {
      /** do something */
    })

    Be careful: this transformation doesn't mean that the function works now asynchronously; Just is converting try-catch interface into callback(err, data).

    License

    MIT © Kiko Beats

    Install

    npm i osom

    Homepage

    osom.js.org

    DownloadsWeekly Downloads

    206

    Version

    3.1.2

    License

    MIT

    Unpacked Size

    14 kB

    Total Files

    4

    Last publish

    Collaborators

    • kikobeats