[javascript] How can I convert a string to boolean in JavaScript?

The expression you're looking for simply is

/^true$/i.test(myValue)

as in

var isTrueSet = /^true$/i.test(myValue);

This tests myValue against a regular expression , case-insensitive, and doesn't modify the prototype.

Examples:

/^true$/i.test("true"); // true
/^true$/i.test("TRUE"); // true
/^true$/i.test("tRuE"); // true
/^true$/i.test(" tRuE"); // false (notice the space at the beginning)
/^true$/i.test("untrue"); // false (some other solutions here will incorrectly return true
/^true$/i.test("false");// returns false
/^true$/i.test("xyz");  // returns false