How to use the @antv/util.isFunction function in @antv/util

private getLabelConfig(region, labelOptions, index) {
    let x = 0;
    let y = 0;
    let style: any = {};
    let text = labelOptions.text;
    if (isFunction(text)) {
      text = text(region);
    } else if (isArray(text)) {
      text = text[index];
    }
    const { position } = labelOptions;
    const pos = position.split('-');
    const dim = region.name.split('-');
    // x方向
    if (dim[1] === 'left') {
      if (pos[0] === 'inner') {
        x = region.bbox.maxX - labelOptions.offset;
        style.textAlign = 'right';
      }
      if (pos[0] === 'outter') {
        x = region.bbox.minX + labelOptions.offset;
        style.textAlign = 'left';

private _gridParser() {
    const { grid: gridCfg } = this.localProps;
    const { style } = gridCfg;

    if (_.isFunction(style)) {
      // @see g2/component/src/axis/base:_renderGrid
      this.config.grid = (text: string, index: number, count: number) => {
        const cfg = style(text, index, count);
        return _.deepMix({}, _.get(this.themeConfig, `grid.style`), cfg);
      };
    } else if (style) {
      this.config.grid = style;
      this.applyThemeConfig('grid');
    }
  }

Util.each(items, (item: CommonCfg, index: number) => {
      const checked = item.checked;
      const value = this.formatterValue(item.value); // 按照 formatter 配置格式化文本
      const originColor = item.marker.fill || item.marker.stroke;
      const color = checked ? originColor : unSelectedColor;
      let itemDom;
      if (Util.isFunction(itemTpl)) {
        // 用户声明了回调
        const domStr = itemTpl(value, color, checked, index);
        itemDom = domUtil.createDom(domStr);
      } else {
        itemDom = domUtil.createDom(itemTpl);
        const textDom = _findNodeByClass(itemDom, `${prefixClassName}-item-text`);
        textDom.innerHTML = value;
      }
      itemStyle.color = color; // 设置为当前状态对应的文本颜色
      markerStyle.backgroundColor = color; // 设置为当前状态 marker 的背景色

      domUtil.modifyCSS(itemDom, itemStyle);
      itemDom.setAttribute('data-checked', checked); // 存储当前的选中状态
      itemDom.setAttribute('data-value', item.value); // 存储 item 的原始值
      itemDom.setAttribute('data-color', originColor); // 存储 item 的原始颜色

public parseColor() {
    const props = this.plot.options;
    const config: DataPointType = {};
    const colorMappingField = this._getColorMappingField();
    if (colorMappingField) {
      config.fields = colorMappingField;
    }
    if (_.has(props, 'color')) {
      const color = props.color;
      if (_.isString(color)) {
        config.values = [color];
      } else if (_.isFunction(color)) {
        config.callback = color;
      } else {
        config.values = color as [];
      }
    }
    this.config.color = config;
  }

const labelProps = this.originConfig;
    const theme = this.plot.getPlotTheme();
    const config: DataPointType = { ...labelProps };
    this._parseOffset(labelProps, config);
    if (labelProps.position) {
      if (_.isFunction(labelProps.position)) {
        config.position = labelProps.position(val);
      } else {
        config.position = labelProps.position;
      }
    }
    if (labelProps.formatter) {
      config.formatter = labelProps.formatter;
    }
    if (labelProps.style) {
      if (_.isFunction(labelProps.style)) {
        config.textStyle = labelProps.style(val);
      } else {
        config.textStyle = labelProps.style;
      }
    }
    config.textStyle = _.deepMix({}, _.get(theme, 'label.style'), config.textStyle);
    if (labelProps.autoRotate) {
      config.autoRotate = labelProps.autoRotate;
    }

    return config;
  }

public setLabelPosition(point, originPoint, index, originPosition) {
    let position = originPosition;
    if (_.isFunction(position)) {
      position = position(originPoint);
    }
    const coord = this.get('coord');
    const point0 = coord.convertPoint(originPoint.points[0]);
    const point1 = coord.convertPoint(originPoint.points[2]);
    const width = (point0.x - point1.x) / 2;
    const height = (point0.y - point1.y) / 2;

    switch (position) {
      case 'right':
        point.x -= width;
        point.y += height;
        point.textAlign = point.textAlign || 'left';
        break;
      case 'left':
        point.x += width;

export function getAnimateParam(animateCfg, index, id) {
  return {
    delay: _.isFunction(animateCfg.delay) ? animateCfg.delay(index, id) : animateCfg.delay,
    easing: _.isFunction(animateCfg.easing) ? animateCfg.easing(index, id) : animateCfg.easing,
    duration: _.isFunction(animateCfg.duration) ? animateCfg.duration(index, id) : animateCfg.duration,
    callback: animateCfg.callback,
  };
}

private _parseColor(props, config) {
    if (_.isString(props.color)) {
      config.values = [props.color];
    } else if (_.isFunction(props.color)) {
      config.callback = props.color;
    } else if (_.isArray(props.color)) {
      config.values = props.color;
    }
  }
}

shape.setSilent('animating', true);
    animateCfg.callback = () => {
      if (shape && !shape.get('destroyed')) {
        shape.attr('clip', null);
        shape.setSilent('cacheShape', null);
        shape.setSilent('animating', false);
        clip.remove();
        if (direction === 'antiClockWise') {
          shape.attr('path', path);
        }
      }
    };
    /** 执行动画 */
    /** 准备动画参数 */
    let delay = animateCfg.delay;
    if (_.isFunction(delay)) {
      delay = animateCfg.delay(index);
    }
    let easing = animateCfg.easing;
    if (_.isFunction(easing)) {
      easing = animateCfg.easing(index);
    }
    /** 动起来 */
    clip.animate(uniform, animateCfg.duration, easing, animateCfg.callback, delay);
  }

  setShapeInfo(shape, startAngle, endAngle);
}

export function compare(origin, condition) {
  if (!_.isFunction(condition)) {
    const { name, exp } = condition;
    if (_.isFunction(exp)) {
      return exp(origin[name]);
    }
    return origin[name] === exp;
  }
  return condition(origin);
}