The source code

    /**
     * @class Ext.data.ArrayReader
     * @extends Ext.data.JsonReader
     * <p>Data reader class to create an Array of {@link Ext.data.Record} objects from an Array.
     * Each element of that Array represents a row of data fields. The
     * fields are pulled into a Record object using as a subscript, the <code>mapping</code> property
     * of the field definition if it exists, or the field's ordinal position in the definition.</p>
     * <p>Example code:</p>
     * <pre><code>
    var Employee = Ext.data.Record.create([
        {name: 'name', mapping: 1},         // "mapping" only needed if an "id" field is present which
        {name: 'occupation', mapping: 2}    // precludes using the ordinal position as the index.
    ]);
    var myReader = new Ext.data.ArrayReader({
        {@link #idIndex}: 0
    }, Employee);
    </code></pre>
     * <p>This would consume an Array like this:</p>
     * <pre><code>
    [ [1, 'Bill', 'Gardener'], [2, 'Ben', 'Horticulturalist'] ]
     * </code></pre>
     * @constructor
     * Create a new ArrayReader
     * @param {Object} meta Metadata configuration options.
     * @param {Array/Object} recordType
     * <p>Either an Array of {@link Ext.data.Field Field} definition objects (which
     * will be passed to {@link Ext.data.Record#create}, or a {@link Ext.data.Record Record}
     * constructor created from {@link Ext.data.Record#create}.</p>
     */
    Ext.data.ArrayReader = Ext.extend(Ext.data.JsonReader, {
        /**
         * @cfg {String} successProperty
         * @hide
         */
        /**
         * @cfg {Number} id (optional) The subscript within row Array that provides an ID for the Record.
         * Deprecated. Use {@link #idIndex} instead.
         */
        /**
         * @cfg {Number} idIndex (optional) The subscript within row Array that provides an ID for the Record.
         */
        /**
         * Create a data block containing Ext.data.Records from an Array.
         * @param {Object} o An Array of row objects which represents the dataset.
         * @return {Object} data A data block which is used by an Ext.data.Store object as
         * a cache of Ext.data.Records.
         */
        readRecords : function(o){
            this.arrayData = o;
            var s = this.meta,
                sid = s ? Ext.num(s.idIndex, s.id) : null,
                recordType = this.recordType,
                fields = recordType.prototype.fields,
                records = [],
                success = true,
                v;

            var root = this.getRoot(o);

            for(var i = 0, len = root.length; i < len; i++) {
                var n = root[i],
                    values = {},
                    id = ((sid || sid === 0) && n[sid] !== undefined && n[sid] !== "" ? n[sid] : null);
                for(var j = 0, jlen = fields.length; j < jlen; j++) {
                    var f = fields.items[j],
                        k = f.mapping !== undefined && f.mapping !== null ? f.mapping : j;
                    v = n[k] !== undefined ? n[k] : f.defaultValue;
                    v = f.convert(v, n);
                    values[f.name] = v;
                }
                var record = new recordType(values, id);
                record.json = n;
                records[records.length] = record;
            }

            var totalRecords = records.length;

            if(s.totalProperty) {
                v = parseInt(this.getTotal(o), 10);
                if(!isNaN(v)) {
                    totalRecords = v;
                }
            }
            if(s.successProperty){
                v = this.getSuccess(o);
                if(v === false || v === 'false'){
                    success = false;
                }
            }

            return {
                success : success,
                records : records,
                totalRecords : totalRecords
            };
        }
    });