List.js

/**
 * List for data storage
 * @module echarts/data/List
 */
define(function (require) {

    var UNDEFINED = 'undefined';
    var globalObj = typeof window === 'undefined' ? global : window;
    var Float64Array = typeof globalObj.Float64Array === UNDEFINED
        ? Array : globalObj.Float64Array;
    var Int32Array = typeof globalObj.Int32Array === UNDEFINED
        ? Array : globalObj.Int32Array;

    var dataCtors = {
        'float': Float64Array,
        'int': Int32Array,
        // Ordinal data type can be string or int
        'ordinal': Array,
        'number': Array,
        'time': Array
    };

    var Model = require('../model/Model');
    var DataDiffer = require('./DataDiffer');

    var zrUtil = require('zrender/core/util');
    var modelUtil = require('../util/model');
    var isObject = zrUtil.isObject;

    var IMMUTABLE_PROPERTIES = [
        'stackedOn', '_nameList', '_idList', '_rawData'
    ];

    var transferImmuProperties = function (a, b, wrappedMethod) {
        zrUtil.each(IMMUTABLE_PROPERTIES.concat(wrappedMethod || []), function (propName) {
            if (b.hasOwnProperty(propName)) {
                a[propName] = b[propName];
            }
        });
    };

    /**
     * @constructor
     * @alias module:echarts/data/List
     *
     * @param {Array.<string>} dimensions
     *        Dimensions should be concrete names like x, y, z, lng, lat, angle, radius
     * @param {module:echarts/model/Model} hostModel
     */
    var List = function (dimensions, hostModel) {

        dimensions = dimensions || ['x', 'y'];

        var dimensionInfos = {};
        var dimensionNames = [];
        for (var i = 0; i < dimensions.length; i++) {
            var dimensionName;
            var dimensionInfo = {};
            if (typeof dimensions[i] === 'string') {
                dimensionName = dimensions[i];
                dimensionInfo = {
                    name: dimensionName,
                    stackable: false,
                    // Type can be 'float', 'int', 'number'
                    // Default is number, Precision of float may not enough
                    type: 'number'
                };
            }
            else {
                dimensionInfo = dimensions[i];
                dimensionName = dimensionInfo.name;
                dimensionInfo.type = dimensionInfo.type || 'number';
            }
            dimensionNames.push(dimensionName);
            dimensionInfos[dimensionName] = dimensionInfo;
        }
        /**
         * @readOnly
         * @type {Array.<string>}
         */
        this.dimensions = dimensionNames;

        /**
         * Infomation of each data dimension, like data type.
         * @type {Object}
         */
        this._dimensionInfos = dimensionInfos;

        /**
         * @type {module:echarts/model/Model}
         */
        this.hostModel = hostModel;

        /**
         * Indices stores the indices of data subset after filtered.
         * This data subset will be used in chart.
         * @type {Array.<number>}
         * @readOnly
         */
        this.indices = [];

        /**
         * Data storage
         * @type {Object.<key, TypedArray|Array>}
         * @private
         */
        this._storage = {};

        /**
         * @type {Array.<string>}
         */
        this._nameList = [];
        /**
         * @type {Array.<string>}
         */
        this._idList = [];
        /**
         * Models of data option is stored sparse for optimizing memory cost
         * @type {Array.<module:echarts/model/Model>}
         * @private
         */
        this._optionModels = [];

        /**
         * @param {module:echarts/data/List}
         */
        this.stackedOn = null;

        /**
         * Global visual properties after visual coding
         * @type {Object}
         * @private
         */
        this._visual = {};

        /**
         * Globel layout properties.
         * @type {Object}
         * @private
         */
        this._layout = {};

        /**
         * Item visual properties after visual coding
         * @type {Array.<Object>}
         * @private
         */
        this._itemVisuals = [];

        /**
         * Item layout properties after layout
         * @type {Array.<Object>}
         * @private
         */
        this._itemLayouts = [];

        /**
         * Graphic elemnents
         * @type {Array.<module:zrender/Element>}
         * @private
         */
        this._graphicEls = [];

        /**
         * @type {Array.<Array|Object>}
         * @private
         */
        this._rawData;

        /**
         * @type {Object}
         * @private
         */
        this._extent;
    };

    var listProto = List.prototype;

    listProto.type = 'list';

    /**
     * Get dimension name
     * @param {string|number} dim
     *        Dimension can be concrete names like x, y, z, lng, lat, angle, radius
     *        Or a ordinal number. For example getDimensionInfo(0) will return 'x' or 'lng' or 'radius'
     * @return {string} Concrete dim name.
     */
    listProto.getDimension = function (dim) {
        if (!isNaN(dim)) {
            dim = this.dimensions[dim] || dim;
        }
        return dim;
    };
    /**
     * Get type and stackable info of particular dimension
     * @param {string|number} dim
     *        Dimension can be concrete names like x, y, z, lng, lat, angle, radius
     *        Or a ordinal number. For example getDimensionInfo(0) will return 'x' or 'lng' or 'radius'
     */
    listProto.getDimensionInfo = function (dim) {
        return zrUtil.clone(this._dimensionInfos[this.getDimension(dim)]);
    };

    /**
     * Initialize from data
     * @param {Array.<Object|number|Array>} data
     * @param {Array.<string>} [nameList]
     * @param {Function} [dimValueGetter] (dataItem, dimName, dataIndex, dimIndex) => number
     */
    listProto.initData = function (data, nameList, dimValueGetter) {
        data = data || [];

        if (!zrUtil.isArray(data)) {
            throw new Error('Invalid data.');
        }

        this._rawData = data;

        // Clear
        var storage = this._storage = {};
        var indices = this.indices = [];

        var dimensions = this.dimensions;
        var size = data.length;
        var dimensionInfoMap = this._dimensionInfos;

        var idList = [];
        var nameRepeatCount = {};

        nameList = nameList || [];

        // Init storage
        for (var i = 0; i < dimensions.length; i++) {
            var dimInfo = dimensionInfoMap[dimensions[i]];
            var DataCtor = dataCtors[dimInfo.type];
            storage[dimensions[i]] = new DataCtor(size);
        }

        // Default dim value getter
        dimValueGetter = dimValueGetter || function (dataItem, dimName, dataIndex, dimIndex) {
            var value = modelUtil.getDataItemValue(dataItem);
            return modelUtil.converDataValue(
                zrUtil.isArray(value)
                    ? value[dimIndex]
                    // If value is a single number or something else not array.
                    : value,
                dimensionInfoMap[dimName]
            );
        };

        for (var idx = 0; idx < data.length; idx++) {
            var dataItem = data[idx];
            // Each data item is value
            // [1, 2]
            // 2
            // Bar chart, line chart which uses category axis
            // only gives the 'y' value. 'x' value is the indices of cateogry
            // Use a tempValue to normalize the value to be a (x, y) value

            // Store the data by dimensions
            for (var k = 0; k < dimensions.length; k++) {
                var dim = dimensions[k];
                var dimStorage = storage[dim];
                // PENDING NULL is empty or zero
                dimStorage[idx] = dimValueGetter(dataItem, dim, idx, k);
            }

            indices.push(idx);
        }

        // Use the name in option and create id
        for (var i = 0; i < data.length; i++) {
            var id = '';
            if (!nameList[i]) {
                nameList[i] = data[i].name;
                // Try using the id in option
                id = data[i].id;
            }
            var name = nameList[i] || '';
            if (!id && name) {
                // Use name as id and add counter to avoid same name
                nameRepeatCount[name] = nameRepeatCount[name] || 0;
                id = name;
                if (nameRepeatCount[name] > 0) {
                    id += '__ec__' + nameRepeatCount[name];
                }
                nameRepeatCount[name]++;
            }
            id && (idList[i] = id);
        }

        this._nameList = nameList;
        this._idList = idList;
    };

    /**
     * @return {number}
     */
    listProto.count = function () {
        return this.indices.length;
    };

    /**
     * Get value. Return NaN if idx is out of range.
     * @param {string} dim Dim must be concrete name.
     * @param {number} idx
     * @param {boolean} stack
     * @return {number}
     */
    listProto.get = function (dim, idx, stack) {
        var storage = this._storage;
        var dataIndex = this.indices[idx];

        // If value not exists
        if (dataIndex == null) {
            return NaN;
        }

        var value = storage[dim] && storage[dim][dataIndex];
        // FIXME ordinal data type is not stackable
        if (stack) {
            var dimensionInfo = this._dimensionInfos[dim];
            if (dimensionInfo && dimensionInfo.stackable) {
                var stackedOn = this.stackedOn;
                while (stackedOn) {
                    // Get no stacked data of stacked on
                    var stackedValue = stackedOn.get(dim, idx);
                    // Considering positive stack, negative stack and empty data
                    if ((value >= 0 && stackedValue > 0)  // Positive stack
                        || (value <= 0 && stackedValue < 0) // Negative stack
                    ) {
                        value += stackedValue;
                    }
                    stackedOn = stackedOn.stackedOn;
                }
            }
        }
        return value;
    };

    /**
     * Get value for multi dimensions.
     * @param {Array.<string>} [dimensions] If ignored, using all dimensions.
     * @param {number} idx
     * @param {boolean} stack
     * @return {number}
     */
    listProto.getValues = function (dimensions, idx, stack) {
        var values = [];

        if (!zrUtil.isArray(dimensions)) {
            stack = idx;
            idx = dimensions;
            dimensions = this.dimensions;
        }

        for (var i = 0, len = dimensions.length; i < len; i++) {
            values.push(this.get(dimensions[i], idx, stack));
        }

        return values;
    };

    /**
     * If value is NaN. Inlcuding '-'
     * @param {string} dim
     * @param {number} idx
     * @return {number}
     */
    listProto.hasValue = function (idx) {
        var dimensions = this.dimensions;
        var dimensionInfos = this._dimensionInfos;
        for (var i = 0, len = dimensions.length; i < len; i++) {
            if (
                // Ordinal type can be string or number
                dimensionInfos[dimensions[i]].type !== 'ordinal'
                && isNaN(this.get(dimensions[i], idx))
            ) {
                return false;
            }
        }
        return true;
    };

    /**
     * Get extent of data in one dimension
     * @param {string} dim
     * @param {boolean} stack
     */
    listProto.getDataExtent = function (dim, stack) {
        var dimData = this._storage[dim];
        var dimInfo = this.getDimensionInfo(dim);
        stack = (dimInfo && dimInfo.stackable) && stack;
        var dimExtent = (this._extent || (this._extent = {}))[dim + (!!stack)];
        var value;
        if (dimExtent) {
            return dimExtent;
        }
        // var dimInfo = this._dimensionInfos[dim];
        if (dimData) {
            var min = Infinity;
            var max = -Infinity;
            // var isOrdinal = dimInfo.type === 'ordinal';
            for (var i = 0, len = this.count(); i < len; i++) {
                value = this.get(dim, i, stack);
                // FIXME
                // if (isOrdinal && typeof value === 'string') {
                //     value = zrUtil.indexOf(dimData, value);
                // }
                value < min && (min = value);
                value > max && (max = value);
            }
            return (this._extent[dim + stack] = [min, max]);
        }
        else {
            return [Infinity, -Infinity];
        }
    };

    /**
     * Get sum of data in one dimension
     * @param {string} dim
     * @param {boolean} stack
     */
    listProto.getSum = function (dim, stack) {
        var dimData = this._storage[dim];
        var sum = 0;
        if (dimData) {
            for (var i = 0, len = this.count(); i < len; i++) {
                var value = this.get(dim, i, stack);
                if (!isNaN(value)) {
                    sum += value;
                }
            }
        }
        return sum;
    };

    /**
     * Retreive the index with given value
     * @param {number} idx
     * @param {number} value
     * @return {number}
     */
    // FIXME Precision of float value
    listProto.indexOf = function (dim, value) {
        var storage = this._storage;
        var dimData = storage[dim];
        var indices = this.indices;

        if (dimData) {
            for (var i = 0, len = indices.length; i < len; i++) {
                var rawIndex = indices[i];
                if (dimData[rawIndex] === value) {
                    return i;
                }
            }
        }
        return -1;
    };

    /**
     * Retreive the index with given name
     * @param {number} idx
     * @param {number} name
     * @return {number}
     */
    listProto.indexOfName = function (name) {
        var indices = this.indices;
        var nameList = this._nameList;

        for (var i = 0, len = indices.length; i < len; i++) {
            var rawIndex = indices[i];
            if (nameList[rawIndex] === name) {
                return i;
            }
        }

        return -1;
    };

    /**
     * Retreive the index of nearest value
     * @param {string} dim
     * @param {number} value
     * @param {boolean} stack If given value is after stacked
     * @return {number}
     */
    listProto.indexOfNearest = function (dim, value, stack) {
        var storage = this._storage;
        var dimData = storage[dim];

        if (dimData) {
            var minDist = Number.MAX_VALUE;
            var nearestIdx = -1;
            for (var i = 0, len = this.count(); i < len; i++) {
                var diff = value - this.get(dim, i, stack);
                var dist = Math.abs(diff);
                if (dist < minDist
                    // For the case of two data are same on xAxis, which has sequence data.
                    // Show the nearest index
                    // https://github.com/ecomfe/echarts/issues/2869
                    || (dist === minDist && diff > 0)
                ) {
                    minDist = dist;
                    nearestIdx = i;
                }
            }
            return nearestIdx;
        }
        return -1;
    };

    /**
     * Get raw data index
     * @param {number} idx
     * @return {number}
     */
    listProto.getRawIndex = function (idx) {
        var rawIdx = this.indices[idx];
        return rawIdx == null ? -1 : rawIdx;
    };

    /**
     * Get raw data item
     * @param {number} idx
     * @return {number}
     */
    listProto.getRawDataItem = function (idx) {
        return (this._rawData || [])[this.getRawIndex(idx)];
    };

    /**
     * @param {number} idx
     * @param {boolean} [notDefaultIdx=false]
     * @return {string}
     */
    listProto.getName = function (idx) {
        return this._nameList[this.indices[idx]] || '';
    };

    /**
     * @param {number} idx
     * @param {boolean} [notDefaultIdx=false]
     * @return {string}
     */
    listProto.getId = function (idx) {
        return this._idList[this.indices[idx]] || (this.getRawIndex(idx) + '');
    };


    function normalizeDimensions(dimensions) {
        if (!zrUtil.isArray(dimensions)) {
            dimensions = [dimensions];
        }
        return dimensions;
    }

    /**
     * Data iteration
     * @param {string|Array.<string>}
     * @param {Function} cb
     * @param {boolean} [stack=false]
     * @param {*} [context=this]
     *
     * @example
     *  list.each('x', function (x, idx) {});
     *  list.each(['x', 'y'], function (x, y, idx) {});
     *  list.each(function (idx) {})
     */
    listProto.each = function (dimensions, cb, stack, context) {
        if (typeof dimensions === 'function') {
            context = stack;
            stack = cb;
            cb = dimensions;
            dimensions = [];
        }

        dimensions = zrUtil.map(
            normalizeDimensions(dimensions), this.getDimension, this
        );

        var value = [];
        var dimSize = dimensions.length;
        var indices = this.indices;

        context = context || this;

        for (var i = 0; i < indices.length; i++) {
            if (dimSize === 0) {
                cb.call(context, i);
            }
            // Simple optimization
            else if (dimSize === 1) {
                cb.call(context, this.get(dimensions[0], i, stack), i);
            }
            else {
                for (var k = 0; k < dimSize; k++) {
                    value[k] = this.get(dimensions[k], i, stack);
                }
                // Index
                value[k] = i;
                cb.apply(context, value);
            }
        }
    };

    /**
     * Data filter
     * @param {string|Array.<string>}
     * @param {Function} cb
     * @param {boolean} [stack=false]
     * @param {*} [context=this]
     */
    listProto.filterSelf = function (dimensions, cb, stack, context) {
        if (typeof dimensions === 'function') {
            context = stack;
            stack = cb;
            cb = dimensions;
            dimensions = [];
        }

        dimensions = zrUtil.map(
            normalizeDimensions(dimensions), this.getDimension, this
        );

        var newIndices = [];
        var value = [];
        var dimSize = dimensions.length;
        var indices = this.indices;

        context = context || this;

        for (var i = 0; i < indices.length; i++) {
            var keep;
            // Simple optimization
            if (dimSize === 1) {
                keep = cb.call(
                    context, this.get(dimensions[0], i, stack), i
                );
            }
            else {
                for (var k = 0; k < dimSize; k++) {
                    value[k] = this.get(dimensions[k], i, stack);
                }
                value[k] = i;
                keep = cb.apply(context, value);
            }
            if (keep) {
                newIndices.push(indices[i]);
            }
        }

        this.indices = newIndices;

        // Reset data extent
        this._extent = {};

        return this;
    };

    /**
     * Data mapping to a plain array
     * @param {string|Array.<string>} [dimensions]
     * @param {Function} cb
     * @param {boolean} [stack=false]
     * @param {*} [context=this]
     * @return {Array}
     */
    listProto.mapArray = function (dimensions, cb, stack, context) {
        if (typeof dimensions === 'function') {
            context = stack;
            stack = cb;
            cb = dimensions;
            dimensions = [];
        }

        var result = [];
        this.each(dimensions, function () {
            result.push(cb && cb.apply(this, arguments));
        }, stack, context);
        return result;
    };

    function cloneListForMapAndSample(original, excludeDimensions) {
        var allDimensions = original.dimensions;
        var list = new List(
            zrUtil.map(allDimensions, original.getDimensionInfo, original),
            original.hostModel
        );
        // FIXME If needs stackedOn, value may already been stacked
        transferImmuProperties(list, original, original._wrappedMethods);

        var storage = list._storage = {};
        var originalStorage = original._storage;
        // Init storage
        for (var i = 0; i < allDimensions.length; i++) {
            var dim = allDimensions[i];
            var dimStore = originalStorage[dim];
            if (zrUtil.indexOf(excludeDimensions, dim) >= 0) {
                storage[dim] = new dimStore.constructor(
                    originalStorage[dim].length
                );
            }
            else {
                // Direct reference for other dimensions
                storage[dim] = originalStorage[dim];
            }
        }
        return list;
    }

    /**
     * Data mapping to a new List with given dimensions
     * @param {string|Array.<string>} dimensions
     * @param {Function} cb
     * @param {boolean} [stack=false]
     * @param {*} [context=this]
     * @return {Array}
     */
    listProto.map = function (dimensions, cb, stack, context) {
        dimensions = zrUtil.map(
            normalizeDimensions(dimensions), this.getDimension, this
        );

        var list = cloneListForMapAndSample(this, dimensions);
        // Following properties are all immutable.
        // So we can reference to the same value
        var indices = list.indices = this.indices;

        var storage = list._storage;

        var tmpRetValue = [];
        this.each(dimensions, function () {
            var idx = arguments[arguments.length - 1];
            var retValue = cb && cb.apply(this, arguments);
            if (retValue != null) {
                // a number
                if (typeof retValue === 'number') {
                    tmpRetValue[0] = retValue;
                    retValue = tmpRetValue;
                }
                for (var i = 0; i < retValue.length; i++) {
                    var dim = dimensions[i];
                    var dimStore = storage[dim];
                    var rawIdx = indices[idx];
                    if (dimStore) {
                        dimStore[rawIdx] = retValue[i];
                    }
                }
            }
        }, stack, context);

        return list;
    };

    /**
     * Large data down sampling on given dimension
     * @param {string} dimension
     * @param {number} rate
     * @param {Function} sampleValue
     * @param {Function} sampleIndex Sample index for name and id
     */
    listProto.downSample = function (dimension, rate, sampleValue, sampleIndex) {
        var list = cloneListForMapAndSample(this, [dimension]);
        var storage = this._storage;
        var targetStorage = list._storage;

        var originalIndices = this.indices;
        var indices = list.indices = [];

        var frameValues = [];
        var frameIndices = [];
        var frameSize = Math.floor(1 / rate);

        var dimStore = targetStorage[dimension];
        var len = this.count();
        // Copy data from original data
        for (var i = 0; i < storage[dimension].length; i++) {
            targetStorage[dimension][i] = storage[dimension][i];
        }
        for (var i = 0; i < len; i += frameSize) {
            // Last frame
            if (frameSize > len - i) {
                frameSize = len - i;
                frameValues.length = frameSize;
            }
            for (var k = 0; k < frameSize; k++) {
                var idx = originalIndices[i + k];
                frameValues[k] = dimStore[idx];
                frameIndices[k] = idx;
            }
            var value = sampleValue(frameValues);
            var idx = frameIndices[sampleIndex(frameValues, value) || 0];
            // Only write value on the filtered data
            dimStore[idx] = value;
            indices.push(idx);
        }
        return list;
    };

    /**
     * Get model of one data item.
     *
     * @param {number} idx
     */
    // FIXME Model proxy ?
    listProto.getItemModel = function (idx) {
        var hostModel = this.hostModel;
        idx = this.indices[idx];
        return new Model(this._rawData[idx], hostModel, hostModel && hostModel.ecModel);
    };

    /**
     * Create a data differ
     * @param {module:echarts/data/List} otherList
     * @return {module:echarts/data/DataDiffer}
     */
    listProto.diff = function (otherList) {
        var idList = this._idList;
        var otherIdList = otherList && otherList._idList;
        return new DataDiffer(
            otherList ? otherList.indices : [], this.indices, function (idx) {
                return otherIdList[idx] || (idx + '');
            }, function (idx) {
                return idList[idx] || (idx + '');
            }
        );
    };
    /**
     * Get visual property.
     * @param {string} key
     */
    listProto.getVisual = function (key) {
        var visual = this._visual;
        return visual && visual[key];
    };

    /**
     * Set visual property
     * @param {string|Object} key
     * @param {*} [value]
     *
     * @example
     *  setVisual('color', color);
     *  setVisual({
     *      'color': color
     *  });
     */
    listProto.setVisual = function (key, val) {
        if (isObject(key)) {
            for (var name in key) {
                if (key.hasOwnProperty(name)) {
                    this.setVisual(name, key[name]);
                }
            }
            return;
        }
        this._visual = this._visual || {};
        this._visual[key] = val;
    };

    /**
     * Set layout property.
     * @param {string} key
     * @param {*} [val]
     */
    listProto.setLayout = function (key, val) {
        if (isObject(key)) {
            for (var name in key) {
                if (key.hasOwnProperty(name)) {
                    this.setLayout(name, key[name]);
                }
            }
            return;
        }
        this._layout[key] = val;
    };

    /**
     * Get layout property.
     * @param  {string} key.
     * @return {*}
     */
    listProto.getLayout = function (key) {
        return this._layout[key];
    };

    /**
     * Get layout of single data item
     * @param {number} idx
     */
    listProto.getItemLayout = function (idx) {
        return this._itemLayouts[idx];
    },

    /**
     * Set layout of single data item
     * @param {number} idx
     * @param {Object} layout
     * @param {boolean=} [merge=false]
     */
    listProto.setItemLayout = function (idx, layout, merge) {
        this._itemLayouts[idx] = merge
            ? zrUtil.extend(this._itemLayouts[idx] || {}, layout)
            : layout;
    },

    /**
     * Get visual property of single data item
     * @param {number} idx
     * @param {string} key
     * @param {boolean} ignoreParent
     */
    listProto.getItemVisual = function (idx, key, ignoreParent) {
        var itemVisual = this._itemVisuals[idx];
        var val = itemVisual && itemVisual[key];
        if (val == null && !ignoreParent) {
            // Use global visual property
            return this.getVisual(key);
        }
        return val;
    },

    /**
     * Set visual property of single data item
     *
     * @param {number} idx
     * @param {string|Object} key
     * @param {*} [value]
     *
     * @example
     *  setItemVisual(0, 'color', color);
     *  setItemVisual(0, {
     *      'color': color
     *  });
     */
    listProto.setItemVisual = function (idx, key, value) {
        var itemVisual = this._itemVisuals[idx] || {};
        this._itemVisuals[idx] = itemVisual;

        if (isObject(key)) {
            for (var name in key) {
                if (key.hasOwnProperty(name)) {
                    itemVisual[name] = key[name];
                }
            }
            return;
        }
        itemVisual[key] = value;
    };

    var setItemDataAndSeriesIndex = function (child) {
        child.seriesIndex = this.seriesIndex;
        child.dataIndex = this.dataIndex;
    };
    /**
     * Set graphic element relative to data. It can be set as null
     * @param {number} idx
     * @param {module:zrender/Element} [el]
     */
    listProto.setItemGraphicEl = function (idx, el) {
        var hostModel = this.hostModel;

        if (el) {
            // Add data index and series index for indexing the data by element
            // Useful in tooltip
            el.dataIndex = idx;
            el.seriesIndex = hostModel && hostModel.seriesIndex;
            if (el.type === 'group') {
                el.traverse(setItemDataAndSeriesIndex, el);
            }
        }

        this._graphicEls[idx] = el;
    };

    /**
     * @param {number} idx
     * @return {module:zrender/Element}
     */
    listProto.getItemGraphicEl = function (idx) {
        return this._graphicEls[idx];
    };

    /**
     * @param {Function} cb
     * @param {*} context
     */
    listProto.eachItemGraphicEl = function (cb, context) {
        zrUtil.each(this._graphicEls, function (el, idx) {
            if (el) {
                cb && cb.call(context, el, idx);
            }
        });
    };

    /**
     * Shallow clone a new list except visual and layout properties, and graph elements.
     * New list only change the indices.
     */
    listProto.cloneShallow = function () {
        var dimensionInfoList = zrUtil.map(this.dimensions, this.getDimensionInfo, this);
        var list = new List(dimensionInfoList, this.hostModel);

        // FIXME
        list._storage = this._storage;

        transferImmuProperties(list, this, this._wrappedMethods);

        list.indices = this.indices.slice();

        return list;
    };

    /**
     * Wrap some method to add more feature
     * @param {string} methodName
     * @param {Function} injectFunction
     */
    listProto.wrapMethod = function (methodName, injectFunction) {
        var originalMethod = this[methodName];
        if (typeof originalMethod !== 'function') {
            return;
        }
        this._wrappedMethods = this._wrappedMethods || [];
        this._wrappedMethods.push(methodName);
        this[methodName] = function () {
            var res = originalMethod.apply(this, arguments);
            return injectFunction.call(this, res);
        };
    };

    return List;
});