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EasyPythonJavaScriptTypeScript

Precise typeof Checker

FunctionsObjects

The native typeof operator is famously coarse: it reports 'object'
for arrays, null, dates, regexes and plain objects alike. Implement
solve(value) that returns the precise lowercase type tag for any
JavaScript value.

Expected outputs

  • solve(null) → 'null'
  • solve([]) → 'array'
  • solve(new Date()) → 'date'
  • solve(/abc/) → 'regexp'
  • solve({}) → 'object'
  • solve('hi') → 'string'
  • solve(undefined) → 'undefined'
  • solve(42) → 'number'

The result must always be a non-empty lowercase string.

Sample tests

Test #1Number literal
Input: [42]
Output: "number"
Test #2String literal
Input: ["hello"]
Output: "string"
Test #3Plain object
Input: [{"a":1}]
Output: "object"
Test #4Arrays are not "object"
Input: [[1,2,3]]
Output: "array"
Test #5null is not "object"
Input: [null]
Output: "null"
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