en/builder/src/echarts3/component/brush/preprocessor.js

import * as zrUtil from 'zrender/src/core/util';
var DEFAULT_TOOLBOX_BTNS = ['rect', 'polygon', 'keep', 'clear'];
export default function (option, isNew) {
  var brushComponents = option && option.brush;

  if (!zrUtil.isArray(brushComponents)) {
    brushComponents = brushComponents ? [brushComponents] : [];
  }

  if (!brushComponents.length) {
    return;
  }

  var brushComponentSpecifiedBtns = [];
  zrUtil.each(brushComponents, function (brushOpt) {
    var tbs = brushOpt.hasOwnProperty('toolbox') ? brushOpt.toolbox : [];

    if (tbs instanceof Array) {
      brushComponentSpecifiedBtns = brushComponentSpecifiedBtns.concat(tbs);
    }
  });
  var toolbox = option && option.toolbox;

  if (zrUtil.isArray(toolbox)) {
    toolbox = toolbox[0];
  }

  if (!toolbox) {
    toolbox = {
      feature: {}
    };
    option.toolbox = [toolbox];
  }

  var toolboxFeature = toolbox.feature || (toolbox.feature = {});
  var toolboxBrush = toolboxFeature.brush || (toolboxFeature.brush = {});
  var brushTypes = toolboxBrush.type || (toolboxBrush.type = []);
  brushTypes.push.apply(brushTypes, brushComponentSpecifiedBtns);
  removeDuplicate(brushTypes);

  if (isNew && !brushTypes.length) {
    brushTypes.push.apply(brushTypes, DEFAULT_TOOLBOX_BTNS);
  }
}

function removeDuplicate(arr) {
  var map = {};
  zrUtil.each(arr, function (val) {
    map[val] = 1;
  });
  arr.length = 0;
  zrUtil.each(map, function (flag, val) {
    arr.push(val);
  });
}