let s1 = '2 + 2' // creates a string primitive
let s2 = new String('2 + 2') // creates a String object
console.log(eval(s1)) // returns the number 4
console.log(eval(s2)) // returns the string "2 + 2"
String primitives and
String
objectsString primitives and
String
objects also give different results when using eval()
. Primitives passed to eval
are treated as source code; String
objects are treated as all other objects areref
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