• Introduction
• Usage
• create
• delete
• retrieve
• update
• Properties
• cidPrefix
• destroy
• fetch
• generateCid
• has
• idAttribute
• initialize
• isNew
• parse
• save
• set
• sync
• toJSON
• url
• urlRoot
• validate
• validationError
• Utils
• Custom Properties
• Extending
• Misc
• History

parse

The parse() method provides a way to transform data provided to the model before it's saved as the model's attributes.

Default Implementation

The default implementation looks like this:

parse: function(response) {
  return response;
},

Usage

Let's say you have an API endpoint located at http://localhost:1337/tweets/1, that returns a tweet that looks like this:

{
  id: 1,
  text: 'An old tweet'
}

If you wanted to retrieve that tweet, you could create this model:

import { Model } from 'lore-models';

const Tweet = Model.extend({
  urlRoot: 'http://localhost:1337/tweets'
});

const tweet = new Tweet({
  id: 1
});

tweet.fetch();

Once the API call returns, tweet.attributes would look like this (exactly mirroring the API response):

{
  id: 1,
  text: 'An old tweet'
}

Sometimes you might want to transform that data though, such as changing the name or value of a property, or adding a new field, which can be a quick way to resolve breaking API changes.

You can do that by defining a parse() like this:

import { Model } from 'lore-models';

const Tweet = Model.extend({
  urlRoot: 'http://localhost:1337/tweets',

  parse: function(response){
    response.message = response.text;
    return response;
  }
});

const tweet = new Tweet({
  id: 1
});

tweet.fetch();

Whatever the API returns will be passed to parse() as response, and whatever that function returns will be saved as the model's attributes. In the code above, we're copying the value of text onto a new attribute called message.

This time, once the API call returns, tweet.attributes will look like this:

{
  id: 1,
  text: 'An old tweet',
  message: 'An old tweet'
}

That's the normal use for parse() - transforming data returned from an API endpoint. But sometimes it's useful to create a model and parse the data provided to it. By default this does not happen.

For example, take a look at the code below:

import { Model } from 'lore-models';

const Tweet = Model.extend({
  urlRoot: 'http://localhost:1337/tweets',

  parse: function(response){
    response.message = response.text;
    return response;
  }
});

const tweet = new Tweet({
  id: 1,
  text: 'An old tweet'
});

If we were to examine tweet.attributes at this point, they would look like this, mirroring the data we provided to the constructor:

{
  id: 1,
  text: 'An old tweet'
}

If we wanted the model to parse that data, we need to tell it to by providing an options object, like this:

const tweet = new Tweet({
  id: 1,
  text: 'An old tweet'
}, {
  parse: true
});

Here we've provided an options object as a second argument to the constructor, and set parse to true. This time tweet.attributes will look like this:

{
  id: 1,
  text: 'An old tweet',
  message: 'An old tweet'
}

Now the data will mirror what we would have gotten by calling the API endpoint.