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I understand that the answer to this is it's in the specs but what, if any, is the logic behind it?

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> !!''
false
> !![]
true

A String, to my understanding, is really an array with some extra functionality added to make text easier to work with, it still does all the array-like things though so why is an empty string falsey but an empty array is truthy?

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    A string is a primitive type and an array is an object. Objects are always truthy. That is a simple rule. Commented Jul 7, 2023 at 9:29
  • null is an object, too. but not truthy. Commented Jul 7, 2023 at 9:30
  • 1
    null is not an object, but a primitive. It has typeof equal to "object", but that is a different story. Commented Jul 7, 2023 at 9:30
  • Strings act in a similar way to arrays, but, in javascript at least, they are not arrays. eg you can reference a character with mystring[0] but you can't add characters with mystring.push("end"). Note that strings are immutable. See this question for more info on strings. Commented Jul 7, 2023 at 9:32

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Let's make it simple:

!!''

An empty string in JavaScript is considered a "falsy" value. It is treated as a boolean false when evaluated in a boolean context.

!![]

Arrays, whether it contains items or not, are considered "truthy" values in Javascript. They are treated as a boolean true when evaluated in a boolean context.

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3 Comments

This appears to just repeat the question - statement of fact rather than reasons.
shall I say, it's by definition that, objects are truthy, empty strings are falsey? I thought I already mentioned the logic, which is the OP is asking.
OP isn't asking about the "logic" of true/false, OP is asking about the philosophical logic - ie the reasoning of why it works like this. OP already stated they know it does work like this. They key is the phrase "the logic behind it"

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