IE11 compatibility: `Array.prototype.find` is not supported

Array.prototype.find is not supported in IE11, and this is the only functions that is blocking for IE11.

I think we should consider either:

• Polyfill Array.prototype.find in the primary build
  • import 'core-js/modules/es6.array.find';
• Remove the use of Array.prototype.find
• Polyfill Array.prototype.find in a separate ES5 build
  • Since this is the only function that is blocking for IE11, it won't increase the build size significantly to justify for a separate build

未指定源文件或测试。首先定位 Array.prototype.find 的使用位置以及主要和 ES5 构建配置，然后检查该库如何针对 IE11 兼容性进行测试。完成的标准是选择并实现所列兼容性方案之一，使这不再是 IE11 剩余的阻塞因素。