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Why does 'Mystery!' <= 'Z' equal true but 'the' <= 'Z' equal false but both 'Mystery!' >= 'A' and 'the' >= 'A' equal true. How does such comparision work?

UkoM
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    Because `'B' < 'a'`. Characters are usually (on most systems) in this order: `..., A, B, ..., Z, ... , a, b, c, ...` – ibrahim mahrir Apr 21 '17 at 19:47
  • it depends on characters' codes. In fact what gets compared are the codes of the symbols. – curveball Apr 21 '17 at 19:47
  • Compare the lowercased version of both operands. – ibrahim mahrir Apr 21 '17 at 19:50
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    @kindUser Just closing it without even reading the duplicate candidate. How typical. – ibrahim mahrir Apr 21 '17 at 19:55
  • @ibrahimmahrir The "on most systems" part is misleading. JavaScript always uses the UTF-16 encoding of the Unicode character set for strings. What might vary by source, user and time is the [locale](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl) but the binary comparison operators always use the UTF-16 lexicographic ordering. – Tom Blodget Apr 22 '17 at 20:20

2 Answers2

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it's comparing the UTF-16 code for the string value. Try the same comparisons with charCodeAt method to understand what's happening here

'y'.charCodeAt() <= 'Z'.charCodeAt()

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/charCodeAt

parallaxis
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Upper case letters before lower case letters.

M = ascii value 77
Z = 90

77 < 90

t = 116
Z = 90 

116 !< 90

See more here: www.asciitable.com

Zac
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