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almost/models.coffee

Created November 26, 2011 20:02
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  1. almost revised this gist Dec 3, 2011. 1 changed file with 2 additions and 2 deletions.
    4 changes: 2 additions & 2 deletions models.coffee
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    Original file line number Diff line number Diff line change
    @@ -4,13 +4,13 @@
    # Email: tom@almostobsolete.net
    # Twitter: @almostobsolete

    # Please consider this code to be MIT licensed.

    # The top part is the setup, see below that for the demo

    # To see this run right away try copy pasting it into the 'Try
    # CoffeeScript' box at http://jashkenas.github.com/coffee-script/

    # Please consider this code to be public domain. I'd appreciate it if you'd tell me if you use it but that's not at all required

    # In the browser we use alert but on Node.JS (which doesn't have alert) let's use console.log instead
    alert ?= console.log

  2. almost revised this gist Dec 3, 2011. 1 changed file with 2 additions and 0 deletions.
    2 changes: 2 additions & 0 deletions models.coffee
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    @@ -4,6 +4,8 @@
    # Email: tom@almostobsolete.net
    # Twitter: @almostobsolete

    # Please consider this code to be MIT licensed.

    # The top part is the setup, see below that for the demo

    # To see this run right away try copy pasting it into the 'Try
  3. almost revised this gist Nov 26, 2011. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion models.coffee
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    Original file line number Diff line number Diff line change
    @@ -49,7 +49,7 @@ class Model
    @attributes[name]
    set: (name, value) =>
    field = @constructor.fields[name]
    throw Error('Trying to set an non-existant property!') if not field
    throw Error('Trying to set an non-existent property!') if not field
    # Ignore a re-setting of the same value
    return if value == @get(name)
    @attributes[name] = value
  4. almost revised this gist Nov 26, 2011. 1 changed file with 2 additions and 0 deletions.
    2 changes: 2 additions & 0 deletions models.coffee
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    Original file line number Diff line number Diff line change
    @@ -4,6 +4,8 @@
    # Email: tom@almostobsolete.net
    # Twitter: @almostobsolete

    # The top part is the setup, see below that for the demo

    # To see this run right away try copy pasting it into the 'Try
    # CoffeeScript' box at http://jashkenas.github.com/coffee-script/

  5. almost revised this gist Nov 26, 2011. 1 changed file with 0 additions and 1 deletion.
    1 change: 0 additions & 1 deletion models.coffee
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    @@ -1,4 +1,3 @@

    # The beginnings of a declarative model syntax for CoffeeScript.
    # SEE: http://almostobsolete.net/declarative-models-in-coffeescript.html
    # Thomas Parslow
  6. almost revised this gist Nov 26, 2011. 1 changed file with 5 additions and 1 deletion.
    6 changes: 5 additions & 1 deletion models.coffee
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    @@ -1,9 +1,13 @@

    # The beginnings of a declarative model syntax for CoffeeScript.
    # SEE: http://almostobsolete.net/declarative-models-in-coffeescript.html
    # Thomas Parslow
    # Email: tom@almostobsolete.net
    # Twitter: @almostobsolete

    # To see this run right away try copy pasting it into the 'Try
    # CoffeeScript' box at http://jashkenas.github.com/coffee-script/

    # In the browser we use alert but on Node.JS (which doesn't have alert) let's use console.log instead
    alert ?= console.log

    @@ -111,4 +115,4 @@ post = user.posts.create

    alert "There are now #{user.posts.length()} posts by #{user.get('username')} and the first is called #{user.posts.at(0).get('title')}"

    user.posts.remove(post)
    user.posts.remove(post)
  7. almost revised this gist Nov 26, 2011. 1 changed file with 3 additions and 3 deletions.
    6 changes: 3 additions & 3 deletions models.coffee
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    @@ -12,10 +12,10 @@ isFunction = (obj) ->

    class Model
    # This is the CoffeeScript syntax to declare a class method
    @field: (name, options) =>
    @field: (name, options) ->
    @fields ?= {}
    @fields[name] = options || {}
    @has_many: (klass, options) =>
    @has_many: (klass, options) ->
    options ?= {}
    options.klass = klass
    options.as ?= klass.name.toLowerCase() + 's'
    @@ -111,4 +111,4 @@ post = user.posts.create

    alert "There are now #{user.posts.length()} posts by #{user.get('username')} and the first is called #{user.posts.at(0).get('title')}"

    user.posts.remove(post)
    user.posts.remove(post)
  8. almost created this gist Nov 26, 2011.
    114 changes: 114 additions & 0 deletions models.coffee
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    @@ -0,0 +1,114 @@
    # The beginnings of a declarative model syntax for CoffeeScript.
    # SEE: http://almostobsolete.net/declarative-models-in-coffeescript.html
    # Thomas Parslow
    # Email: tom@almostobsolete.net
    # Twitter: @almostobsolete

    # In the browser we use alert but on Node.JS (which doesn't have alert) let's use console.log instead
    alert ?= console.log

    isFunction = (obj) ->
    Object.prototype.toString.call(obj) == '[object Function]'

    class Model
    # This is the CoffeeScript syntax to declare a class method
    @field: (name, options) =>
    @fields ?= {}
    @fields[name] = options || {}
    @has_many: (klass, options) =>
    options ?= {}
    options.klass = klass
    options.as ?= klass.name.toLowerCase() + 's'
    @collections ?= {}
    @collections[options.as] = options

    constructor: (attributes) ->
    @attributes = {}
    # Copy in attributes passed in or defaults from the fields as appropriate
    for name, options of @constructor.fields
    # Defaults can be specified as values or as functions
    @attributes[name] = attributes?[name] || if (isFunction(options.default)) then options.default() else options.default
    # Set up collections
    for name,options of @constructor.collections
    @[name] = new Collection(@, options)
    @listeners = {}

    # Events
    bind: (event, listener) =>
    (@listeners[event] ?= []).push(listener)
    emit: (event, args...) =>
    listener(args...) for listener in @listeners[event] if @listeners[event]

    # Getters and setters
    get: (name) =>
    @attributes[name]
    set: (name, value) =>
    field = @constructor.fields[name]
    throw Error('Trying to set an non-existant property!') if not field
    # Ignore a re-setting of the same value
    return if value == @get(name)
    @attributes[name] = value
    # Emit change events!
    @emit('change', name, value)
    @emit("change:#{name}", value)

    # A collection class for has_many relations
    class Collection
    # Using CoffeeScript destructuring bind to extract the bits we need from options
    constructor: (@parent, {as: @field_name, klass: @klass}) ->
    @members = []
    create: (attributes) =>
    @add(new @klass(attributes))
    add: (thing) =>
    @members.push(thing)
    @parent.emit("add:#{@field_name}", thing)
    thing
    remove: (thing) =>
    for _thing, i in @members when _thing == thing
    delete @members[i]
    @parent.emit("remove:#{@field_name}", thing)
    break
    all: =>
    _.clone(@members)
    length: =>
    @members.length
    at: (index) =>
    @members[index]

    # Demo

    class Post extends Model
    @field 'title', default: 'New post!'
    @field 'body'
    # the default is supplied as a closure which is evaluated at object creation time
    @field 'created_at', default: -> new Date()

    class User extends Model
    @field 'username'
    @field 'twitter'
    @has_many Post, as: 'posts'


    # Create a new user
    user = new User(username: 'tom', twitter: 'almostobsolete')
    # Bind to the change event for the title property
    user.bind 'change:username', (value) =>
    alert "Username updated to #{value}"
    # Print out details of posts when they are created by the user
    user.bind 'add:posts', (post) =>
    alert "Post titled #{post.get('title')} was written at #{post.get('created_at')}"
    # Print out details of posts when they are created by the user
    user.bind 'remove:posts', (post) =>
    alert "Post titled #{post.get('title')} was removed"

    # Change the user's username (which will trigger the event bound above)
    user.set('username', 'thomas')

    # Create a blog post associated with the new user (which will trigger the other event)
    post = user.posts.create
    title: 'Declarative Models'
    body: 'One of the useful additions....'

    alert "There are now #{user.posts.length()} posts by #{user.get('username')} and the first is called #{user.posts.at(0).get('title')}"

    user.posts.remove(post)