any是放弃全部的类型检查

unknown

unknown类型是放弃一层类型检查，但还是会在程序可能导致崩溃的error代码上给出错误提示。
https://www.typescriptlang.org/play?#code/DYUwLgBATghgdgEwPYFsBqNgC4IFc4DWcSA7nBALwQBstA3AFAOyKobCURhS4jPzJ0mTgCIAzhIkj+rIRyoBvAL5MWg9gDowSAMrcAlnADmACgCUDfQDMTYAJ4AHEEivQBbYRS8QA5HFwoAEYgUD5mCgwQbrKa2npQhqYWKjLqmOaWNvZOLtFp8t4+VvgAxmD6SHBhEVFqHsAZSkA
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  1. let randomVal: unknown = 666;
  3. randomVal = true
  4. randomVal = "sssss"
  5. randomVal = {}
  7. randomVal.toString()
  8. if(typeof randomVal === 'number'){
  9.   randomVal.toString()
  10. }
  12. randomVal()
  13. if(typeof randomVal === 'function'){
  14.   randomVal()
  15. }