if(negetive number) is true? Is something wrong with js?

Question

Is something wrong with js?

if(\"hello\".indexOf(\"world\")) { // I forgot to add > -1 here
    console.log(\"hello world\");
}

Basically

Answer 1

You can see Truthy and Falsy Values here

The following values are always falsy:

• false
• 0 (zero)
• "" (empty string)
• null
• undefined
• NaN (a special Number value meaning Not-a-Number!)

All other values are truthy, including "0" (zero in quotes), "false" (false in quotes), empty functions, empty arrays, and empty objects.