tess-jl/schemas-lab

Mongo Schemas Lab

Mongoose, MongoDB, Node.js, Express

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Assignment: "... use Jest to test a Validator class and a Schema class of MongoDB

USE TDD Practices

1. Validator class
2. Schema class

Validator

The Validator class is used to validate and cast a single field in an object.

const nameValidator = new Validator('name', {
  type: String,
  required: true
});

const ageValidator = new Validator('age', {
  type: String,
  required: true
});

const colorValidator = new Validator('color', {
  type: String,
  required: true
});

const dog = {
  name: 'spot',
  age: '5',
  weight: '20 lbs'
};

nameValidator.validate(dog) // returns 'spot'
age.validate(dog) // returns 5
colorValidator.validate(dog) // throws error

Testing

• Test that validate method can take an object and return a fields value
• Test that validate method can take an object and throw an error
• Test all permutations:
  • required and field missing
  • required and field there but wrong type
  • required and field there and right type
  • not required and field missing
  • not required and field there but wrong type
  • not required and field there and right type

Implementation

• Validator is initialize with two parameters: field and configuration
  • use your getCaster method from yesterdays lab to get the correct castTo* function based on type from the configuration parameter passed in
• Validator has a validate method that takes an object to validate
  • make sure the field is there if it is required
  • use the castTo* function to cast the field

Schema

The Schema class is used to validate and cast an entire object.

const schema = new Schema({
  dog: {
    type: String,
    required: true
  }, 
  age: {
    type: Number,
    required: true
  },
  weight: {
    type: String
  }
});

const spot = {
  name: 'spot',
  age: 5,
  weight: '20 lbs'
};

const rover = {
  name: 'rover',
  age: '10'
};

const who = {
  age: 'hi'
};

schema.validate(spot) // returns { name: 'spot', age: 5, weight: '20 lbs' }
schema.validate(rover) // returns { name: 'rover', age: 10 };'
schema.validate(who) // throws a errors about name being required and age not being a number

Testing

Don't retest functionality already tested by your Validator tests

• Test that validate method returns the object with all fields cast
• Test that validate method throws an error if the object doesn't follow the schema

Implementation

• Schema is initialized with an object defining a schema (schemaDefinition)
  • use the object to create an array of Validators for each key/value in schemaDefinition and store the array in this.validators Schema has a validate method that takes an object
  • invoke the validate method for each Validator in this.validate"