The source code

/** + * @class Ext.data.Field + *

This class encapsulates the field definition information specified in the field definition objects + * passed to {@link Ext.data.Record#create}.

+ *

Developers do not need to instantiate this class. Instances are created by {@link Ext.data.Record.create} + * and cached in the {@link Ext.data.Record#fields fields} property of the created Record constructor's prototype.

+ */ +Ext.data.Field = function(config){ + if(typeof config == "string"){ + config = {name: config}; + } + Ext.apply(this, config); + + if(!this.type){ + this.type = "auto"; + } + + var st = Ext.data.SortTypes; + // named sortTypes are supported, here we look them up + if(typeof this.sortType == "string"){ + this.sortType = st[this.sortType]; + } + + // set default sortType for strings and dates + if(!this.sortType){ + switch(this.type){ + case "string": + this.sortType = st.asUCString; + break; + case "date": + this.sortType = st.asDate; + break; + default: + this.sortType = st.none; + } + } + + // define once + var stripRe = /[\$,%]/g; + + // prebuilt conversion function for this field, instead of + // switching every time we're reading a value + if(!this.convert){ + var cv, dateFormat = this.dateFormat; + switch(this.type){ + case "": + case "auto": + case undefined: + cv = function(v){ return v; }; + break; + case "string": + cv = function(v){ return (v === undefined || v === null) ? '' : String(v); }; + break; + case "int": + cv = function(v){ + return v !== undefined && v !== null && v !== '' ? + parseInt(String(v).replace(stripRe, ""), 10) : ''; + }; + break; + case "float": + cv = function(v){ + return v !== undefined && v !== null && v !== '' ? + parseFloat(String(v).replace(stripRe, ""), 10) : ''; + }; + break; + case "bool": + case "boolean": + cv = function(v){ return v === true || v === "true" || v == 1; }; + break; + case "date": + cv = function(v){ + if(!v){ + return ''; + } + if(Ext.isDate(v)){ + return v; + } + if(dateFormat){ + if(dateFormat == "timestamp"){ + return new Date(v*1000); + } + if(dateFormat == "time"){ + return new Date(parseInt(v, 10)); + } + return Date.parseDate(v, dateFormat); + } + var parsed = Date.parse(v); + return parsed ? new Date(parsed) : null; + }; + break; + + } + this.convert = cv; + } +}; + +Ext.data.Field.prototype = { +

/** + * @cfg {String} name + * The name by which the field is referenced within the Record. This is referenced by, for example, + * the dataIndex property in column definition objects passed to {@link 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.

+ */ +

/** + * @cfg {String} type + * (Optional) The data type for conversion to displayable value if {@link Ext.data.Field#convert convert} + * has not been specified. Possible values are + *

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

+ */ +

/** + * @cfg {Function} convert + * (Optional) A function which converts the value provided by the Reader into an object that will be stored + * in the Record. It is passed the following parameters:

v : Mixed
The data value as read by the Reader, if undefined will use + * the configured {@link Ext.data.Field#defaultValue defaultValue}.
rec : Mixed
The data object containing the row as read by the Reader. + * Depending on the Reader type, this could be an Array ({@link Ext.data.ArrayReader ArrayReader}), an object + * ({@link Ext.data.JsonReader JsonReader}), or an XML element ({@link Ext.data.XMLReader XMLReader}).

+ *


+// 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.data.Record.create([
+    {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: new Ext.data.JsonReader(
+        {
+            idProperty: 'key',
+            root: 'daRoot',  
+            totalProperty: 'total'
+        },
+        Dude  // recordType
+    )
+});
+
+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'
+    }
+];
+     *

+ */ +

/** + * @cfg {String} dateFormat + * (Optional) A format string for the {@link Date#parseDate 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. + */ + dateFormat: null, +

/** + * @cfg {Mixed} defaultValue + * (Optional) The default value used when a Record is being created by a {@link Ext.data.Reader Reader} + * when the item referenced by the {@link Ext.data.Field#mapping mapping} does not exist in the data + * object (i.e. undefined). (defaults to "") + */ + defaultValue: "", +

/** + * @cfg {String/Number} mapping + *

(Optional) A path expression for use by the {@link Ext.data.DataReader} implementation + * that is creating the {@link Ext.data.Record Record} 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.

+ *

{@link Ext.data.JsonReader}
The mapping is a string containing the javascript + * expression to reference the data from an element of the data item's {@link Ext.data.JsonReader#root root} Array. Defaults to the field name.
{@link Ext.data.XmlReader}
The mapping is an {@link Ext.DomQuery} path to the data + * item relative to the DOM element that represents the {@link Ext.data.XmlReader#record record}. Defaults to the field name.
{@link 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 {@link #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.

+ */ + mapping: null, +

/** + * @cfg {Function} sortType + * (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 {@link 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;
+   }
+}
+     *

+ */ + sortType : null, +

/** + * @cfg {String} sortDir + * (Optional) Initial direction to sort ("ASC" or "DESC"). Defaults to + * "ASC". + */ + sortDir : "ASC", +

/** + * @cfg {Boolean} allowBlank + * (Optional) Used for validating a {@link Ext.data.Record record}, defaults to true. + * An empty value here will cause {@link Ext.data.Record}.{@link Ext.data.Record#isValid isValid} + * to evaluate to false. + */ + allowBlank : true +};