export function isDef(value) {
      return value !== undefined && value !== null;
  }
  export function isObj(x) {
      const type = typeof x;
      return x !== null && (type === 'object' || type === 'function');
  }
  export function isNumber(value) {
      return /^\d+(\.\d+)?$/.test(value);
  }
  export function range(num, min, max) {
      return Math.min(Math.max(num, min), max);
  }
  export function nextTick(fn) {
      setTimeout(() => {
          fn();
      }, 1000 / 30);
  }
  let systemInfo = null;
  export function getSystemInfoSync() {
      if (systemInfo == null) {
          systemInfo = wx.getSystemInfoSync();
      }
      return systemInfo;
  }
  export function addUnit(value) {
      if (!isDef(value)) {
          return undefined;
      }
      value = String(value);
      return isNumber(value) ? `${value}px` : value;
  }