Why does the function in chai isBelow not want to accept a string?

Question

JavaScript

There is a test in which you need to check if the string "test" > "rest" is allowed. To do this, chai assert has the isBelow function.
documentation
link to full documentation
says that it accepts mixed. means it must accept a string.
but when I insert a line it displays an error screen
that it was expected either a number or a date.
Maybe someone has come across this.

Answer 1

Mixed is some kind of wet fantasy of the authors of chai - this type is not in JS, not even in TS or Flow. If separately somewhere in the docks it is not indicated that Mixed is for example number | string, then it remains only to look at the source and try to understand from use what exactly was meant. Apparently, it meant “anything and different every time”, sooooo useful documentation :)
Judging by the code , only Data and number are accepted.
How not to suffer expect('test' > 'rest').to.be.true;:. It seems counter-intuitive, but in fact, such tests are easier to read and maintain.

Answer 2

strings are not checked that way. isBelow() is a number comparison, use
assert.equal('123', '4564', 'not equal')

Answer 3

mixed means more than one type, in this case two - a number and a date.
Based on the documentation, isBelow checks for the condition "the first is less than the second". How are you going to compare strings?