en/builder/src/echarts3/component/dataZoom/history.js

import * as zrUtil from 'zrender/src/core/util';
var each = zrUtil.each;
var ATTR = '\0_ec_hist_store';
/**
 * @param {module:echarts/model/Global} ecModel
 * @param {Object} newSnapshot {dataZoomId, batch: [payloadInfo, ...]}
 */

export function push(ecModel, newSnapshot) {
  var store = giveStore(ecModel); // If previous dataZoom can not be found,
  // complete an range with current range.

  each(newSnapshot, function (batchItem, dataZoomId) {
    var i = store.length - 1;

    for (; i >= 0; i--) {
      var snapshot = store[i];

      if (snapshot[dataZoomId]) {
        break;
      }
    }

    if (i < 0) {
      // No origin range set, create one by current range.
      var dataZoomModel = ecModel.queryComponents({
        mainType: 'dataZoom',
        subType: 'select',
        id: dataZoomId
      })[0];

      if (dataZoomModel) {
        var percentRange = dataZoomModel.getPercentRange();
        store[0][dataZoomId] = {
          dataZoomId: dataZoomId,
          start: percentRange[0],
          end: percentRange[1]
        };
      }
    }
  });
  store.push(newSnapshot);
}
/**
 * @param {module:echarts/model/Global} ecModel
 * @return {Object} snapshot
 */

export function pop(ecModel) {
  var store = giveStore(ecModel);
  var head = store[store.length - 1];
  store.length > 1 && store.pop(); // Find top for all dataZoom.

  var snapshot = {};
  each(head, function (batchItem, dataZoomId) {
    for (var i = store.length - 1; i >= 0; i--) {
      var batchItem = store[i][dataZoomId];

      if (batchItem) {
        snapshot[dataZoomId] = batchItem;
        break;
      }
    }
  });
  return snapshot;
}
/**
 * @param {module:echarts/model/Global} ecModel
 */

export function clear(ecModel) {
  ecModel[ATTR] = null;
}
/**
 * @param {module:echarts/model/Global} ecModel
 * @return {number} records. always >= 1.
 */

export function count(ecModel) {
  return giveStore(ecModel).length;
}
/**
 * [{key: dataZoomId, value: {dataZoomId, range}}, ...]
 * History length of each dataZoom may be different.
 * this._history[0] is used to store origin range.
 * @type {Array.<Object>}
 */

function giveStore(ecModel) {
  var store = ecModel[ATTR];

  if (!store) {
    store = ecModel[ATTR] = [{}];
  }

  return store;
}