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Ext.data.Field

Files

Fields are used to define what a Model is. They aren't instantiated directly - instead, Ext.regModel creates a Field instance for each field configured in a Model. For example, we might set up a model like this:

Ext.regModel('User', {
    fields: [
        'name', 'email',
        {name: 'age', type: 'int'},
        {name: 'gender', type: 'string', defaultValue: 'Unknown'}
    ]
});

Four fields will have been created for the User Model - name, email, age and gender. Note that we specified a couple of different formats here; if we only pass in the string name of the field (as with name and email), the field is set up with the 'auto' type. It's as if we'd done this instead:

Ext.regModel('User', {
    fields: [
        {name: 'name', type: 'auto'},
        {name: 'email', type: 'auto'},
        {name: 'age', type: 'int'},
        {name: 'gender', type: 'string', defaultValue: 'Unknown'}
    ]
});

Types and conversion

The type is important - it's used to automatically convert data passed to the field into the correct format. In our example above, the name and email fields used the 'auto' type and will just accept anything that is passed into them. The 'age' field had an 'int' type however, so if we passed 25.4 this would be rounded to 25.

Sometimes a simple type isn't enough, or we want to perform some processing when we load a Field's data. We can do this using a convert function. Here, we're going to create a new field based on another:

Ext.regModel('User', {
    fields: [
        'name', 'email',
        {name: 'age', type: 'int'},
        {name: 'gender', type: 'string', defaultValue: 'Unknown'},

        {
            name: 'firstName',
            convert: function(value, record) {
                var fullName  = record.get('name'),
                    splits    = fullName.split(" "),
                    firstName = splits[0];

                return firstName;
            }
        }
    ]
});

Now when we create a new User, the firstName is populated automatically based on the name:

var ed = Ext.ModelMgr.create({name: 'Ed Spencer'}, 'User');

console.log(ed.get('firstName')); //logs 'Ed', based on our convert function

In fact, if we log out all of the data inside ed, we'll see this:

console.log(ed.data);

//outputs this:
{
    age: 0,
    email: "",
    firstName: "Ed",
    gender: "Unknown",
    name: "Ed Spencer"
}

The age field has been given a default of zero because we made it an int type. As an auto field, email has defaulted to an empty string. When we registered the User model we set gender's defaultValue to 'Unknown' so we see that now. Let's correct that and satisfy ourselves that the types work as we expect:

ed.set('gender', 'Male');
ed.get('gender'); //returns 'Male'

ed.set('age', 25.4);
ed.get('age'); //returns 25 - we wanted an int, not a float, so no decimal places allowed

Available since: 1.1.0

Defined By

Config options

Ext.data.Field
view source
: Booleanprivate
(Optional) Used for validating a model, defaults to true. ...

(Optional) Used for validating a model, defaults to true. An empty value here will cause Ext.data.Model.isValid to evaluate to false.

Defaults to: true

Available since: 1.1.0

Ext.data.Field
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: Function
(Optional) A function which converts the value provided by the Reader into an object that will be stored in the Model. ...

(Optional) A function which converts the value provided by the Reader into an object that will be stored in the Model. It is passed the following parameters:

  • v : Mixed
    The data value as read by the Reader, if undefined will use the configured defaultValue.
  • rec : Ext.data.Model
    The data object containing the Model as read so far by the Reader. Note that the Model may not be fully populated at this point as the fields are read in the order that they are defined in your fields array.

// example of convert function
function fullName(v, record){
    return record.name.last + ', ' + record.name.first;
}

function location(v, record){
    return !record.city ? '' : (record.city + ', ' + record.state);
}

var Dude = Ext.regModel({
    fields: [
        {name: 'fullname',  convert: fullName},
        {name: 'firstname', mapping: 'name.first'},
        {name: 'lastname',  mapping: 'name.last'},
        {name: 'city', defaultValue: 'homeless'},
        'state',
        {name: 'location',  convert: location}
    ]
});

// create the data store
var store = new Ext.data.Store({
    reader: {
        type: 'json',
        model: 'Dude',
        idProperty: 'key',
        root: 'daRoot',
        totalProperty: 'total'
    }
});

var myData = [
    { key: 1,
      name: { first: 'Fat',    last:  'Albert' }
      // notice no city, state provided in data object
    },
    { key: 2,
      name: { first: 'Barney', last:  'Rubble' },
      city: 'Bedrock', state: 'Stoneridge'
    },
    { key: 3,
      name: { first: 'Cliff',  last:  'Claven' },
      city: 'Boston',  state: 'MA'
    }
];

Available since: 1.1.0

Ext.data.Field
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: String
(Optional) Used when converting received data into a Date when the type is specified as "date". ...

(Optional) Used when converting received data into a Date when the type is specified as "date".

A format string for the Date.parseDate function, or "timestamp" if the value provided by the Reader is a UNIX timestamp, or "time" if the value provided by the Reader is a javascript millisecond timestamp. See Date

Available since: 1.1.0

Ext.data.Field
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: Mixed
(Optional) The default value used when a Model is being created by a Reader when the item referenced by the mapping d...

(Optional) The default value used when a Model is being created by a Reader when the item referenced by the mapping does not exist in the data object (i.e. undefined). (defaults to "")

Defaults to: ""

Available since: 1.1.0

Ext.data.Field
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: String/Number
(Optional) A path expression for use by the Ext.data.DataReader implementation that is creating the Model to extract ...

(Optional) A path expression for use by the Ext.data.DataReader implementation that is creating the Model to extract the Field value from the data object. If the path expression is the same as the field name, the mapping may be omitted.

The form of the mapping expression depends on the Reader being used.

  • Ext.data.JsonReader
    The mapping is a string containing the javascript expression to reference the data from an element of the data item's root Array. Defaults to the field name.
  • Ext.data.XmlReader
    The mapping is an Ext.DomQuery path to the data item relative to the DOM element that represents the record. Defaults to the field name.
  • Ext.data.ArrayReader
    The mapping is a number indicating the Array index of the field's value. Defaults to the field specification's Array position.

If a more complex value extraction strategy is required, then configure the Field with a convert function. This is passed the whole row object, and may interrogate it in whatever way is necessary in order to return the desired data.

Available since: 1.1.0

Ext.data.Field
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: String
The name by which the field is referenced within the Model. ...

The name by which the field is referenced within the Model. This is referenced by, for example, the dataIndex property in column definition objects passed to Ext.grid.ColumnModel.

Note: In the simplest case, if no properties other than name are required, a field definition may consist of just a String for the field name.

Available since: 1.1.0

Ext.data.Field
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: String
(Optional) Initial direction to sort ("ASC" or "DESC"). ...

(Optional) Initial direction to sort ("ASC" or "DESC"). Defaults to "ASC".

Defaults to: "ASC"

Available since: 1.1.0

Ext.data.Field
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: Function
(Optional) A function which converts a Field's value to a comparable value in order to ensure correct sort ordering. ...

(Optional) A function which converts a Field's value to a comparable value in order to ensure correct sort ordering. Predefined functions are provided in Ext.data.SortTypes. A custom sort example:

// current sort     after sort we want
// +-+------+          +-+------+
// |1|First |          |1|First |
// |2|Last  |          |3|Second|
// |3|Second|          |2|Last  |
// +-+------+          +-+------+

sortType: function(value) {
   switch (value.toLowerCase()) // native toLowerCase():
   {
      case 'first': return 1;
      case 'second': return 2;
      default: return 3;
   }
}

Available since: 1.1.0

Ext.data.Field
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: Mixed
(Optional) The data type for automatic conversion from received data to the stored value if convert has not been spec...

(Optional) The data type for automatic conversion from received data to the stored value if convert has not been specified. This may be specified as a string value. Possible values are

  • auto (Default, implies no conversion)
  • string
  • int
  • float
  • boolean
  • date

This may also be specified by referencing a member of the Ext.data.Types class.

Developers may create their own application-specific data types by defining new members of the Ext.data.Types class.

Available since: 1.1.0

Ext.data.Field
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: Boolean
(Optional) Use when converting received data into a Number type (either int or float). ...

(Optional) Use when converting received data into a Number type (either int or float). If the value cannot be parsed, null will be used if useNull is true, otherwise the value will be 0. Defaults to false

Defaults to: false

Available since: 1.1.0

Defined By

Methods

Ext.data.Field
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new( config ) : Ext.data.Field
...

Available since: 1.1.0

Parameters

  • config : Object

Returns