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The as() operators coerces objects of one type to be an object of another. The target type is given as a string argument to the operator. The following types are available:

• "Array"
  "Boolean"
  

• "Map"
  

• "Null"

• "Number"
  

• "RegExp"

• "String"

The following coercions are valid:

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The typeof() operator returns the type of the object to which it is applied. The return value is one of the strings that may be passed to as(). , or one of the other following values:

• "Array"

• "Map"

• "Null"

For example:

nums = [1, 2, 3]
nums_type = nums.typeof() // nums_type = "Array"

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