alamid-schema

name: cover

# alamid-schema

Michael Jaser<br>
    MNUG / July 9th, 2014

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    class: center, middle

.slide-header-left[
    alamid-schema
    ]
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    MNUG / July 9th, 2014
    ]

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# About me

My name is Michael Jaser

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---

## peerigon App

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- Web-Agency / Consultancy
    - specialized in...
      - JavaScript
      - Node.js
      - (Mobile-) Web-Apps
    - teaching Node.js at University of Applied Sciences Augsburg

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## peerigon  - Open Source

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- Framework for modern web-application
    - leverages code-sharing between client & server
    - => splitting up in smaller modules!

---

## alamid-schema

```javascript
    var Schema = require("alamid-schema");

var Panda = new Schema("Panda", {
        name: String,
        age: {
            type: Number,
            required: true
        },
        mood: {
            type: String,
            enum: ["grumpy", "happy"]
        },
        birthday: Date
    });
    ```

---

## alamid-schema

>Extendable mongoose-like schemas for node.js and the browser

- highly influenced by mongoose-schema
    - client & server compatible
    - minimum feature-set
    - extensible with plugins

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## Use it on the server to...

- normalize and validate incoming requests
    - strip private fields from the response
    - use mongoose-like schemas without using mongoose
    - create reusable schemas to be shared with the client

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## Use it on the client to...

- validate forms
    - define view models
    - normalize data

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## Define

```javascript
    var PandaSchema = new Schema({
        name: "panda", //concrete Type
        age: Number,   //abstract type
        friends: {
            type: []
        }
    });
    ```

- supports abstract and concrete type definitions

---

## Extend

```javascript
    var PandaSchema = new Schema({
        name: String,
        age: Number,
        friends: {
            type: Array
        }
    });
    ```

```javascript
    var SuperPanda = PandaSchema.extend("SuperPanda", {
        xRay: true,
        canFly: {
            type: Boolean
        }
    });
    ```
    ---

## Overwriting properties

```javascript
    var Animal = new Schema({
        name: String,
        age: String
    });
    ```

```javascript
    var Panda = Animal.extend("Panda", {
        age: Number
        color: String
    });
    ```

equals...

```javascript
    var Panda = new Schema("Panda", {
        name: String,
        age: Number,   //overwritten
        color: String  //added
    });
    ```
    ---

## Subsets

```javascript
    var Panda = new Schema("Panda", {
        name: String,
        age: Number,
        color: String
    });
    ```

```javascript
    var SubsetPanda = Panda.fields("name", "age");
    ```

equals...

```javascript
    var Panda = new Schema("Panda", {
        name: String,
        age: Number
    });
    ```

---

## Plugins

```javascript
    var Schema = require("alamid-schema");

//activate validation plugon
    Schema.use(require("alamid-schema/plugins/validation");
    ```

- you can add functionality with plugins
    - plugins shipping with _alamid-schema_
      - validation
      - readable / writeable fields (soon)
      - defaults (soon)

---

## Plugin: Validation

```javascript
    var PandaSchema = new Schema({
        name: {
            type: String,
            required: true //required
        },
        age: {
            type: Number,
            min: 9, //min (Number)
            max: 99 //max (Number)
        },
        mood: {
            type: String,
            enum: ["happy", "sleepy"] //enum
        },
        birthday: Date
    });
    ```

---

## Plugin: Validation

```javascript
    var panda = {
        name: "Hugo",
        age: 3,
        mood: "happy"
    };

PandaSchema.validate(panda, function(validation) {
        console.log(validation);
    });
    ```

outputs...

```javascript
    {
        result: false,
        failedFields: {
            age: [ "min" ]
        }
    }
    ```

---

## Custom Validators

```javascript
    var PandaSchema = new Schema({
        age: {
            type: Number,
            validate: oldEnough,
            max: 99
        }
    });
    ```

- function with or without callback
    - _Ok_: `return true;`
    - _Not Ok_:  `return false;`
    - with custom error message  <br> `return "bad-format";`

---

## Custom validator: sync

```javascript
    function oldEnough(age) {
        return age > 18 || "too-young";
    }
    ```

---

## Custom Validator: async

```javascript
    function nameIsUnique(name, callback) {

fs.readFile(__dirname + "/names.json", function(err, names) {
            if(err) {
                throw err;
            }

names = JSON.parse(names);

callback(names.indexOf(name) === -1 || "name-already-taken");
            });
    }
    ```

---

## Validate middleware

```javascript
    function validatorMiddleware(schema) {

return function validate(req, res, next) {
            schema = schema || req.schema;

schema.validate(req.body || {}, function(validation) {

if(!validation.result) {
                    res.validation = validation;
                    next(new Error("Validation failed"));
                    return;
                }

next();
            });
        };
    }
    ```

---

## Roadmap

- more plugins
    - middleware
    - embedded schemas
    - nested structure
    - setters/getters
    - make JSON-Schema compatible?

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## Thank you for listening

[https://github.com/peerigon/alamid-schema](https://github.com/peerigon/alamid-schema)

<br>
    michael.jaser@peerigon.com<br>
    @mmeaku