Get wrong results when use regexp or Symbol as function arguments

Because use JSON.stringify(args) in defaultCacheKey function, it will get wrong results when using regexp or Symbol as function arguments.

The reasons are:

console.log(JSON.stringify(/Sindre Sorhus/));
// => '{}'

console.log(JSON.stringify(/Elvin Peng/));
// => '{}'

console.log(JSON.stringify({foo: Symbol('Sindre Sorhus')}));
// => '{}'

console.log(JSON.stringify({foo: Symbol('Elvin Peng')}));
// =>'{}'

[fregante]

I just realized something, order matters:

JSON.stringify({a: 1, b: 1})
// "{\"a\":1,\"b\":1}"

JSON.stringify({b: 1, a: 1})
// "{\"b\":1,\"a\":1}"

This means that the cache is hit even less than we realize

[sindresorhus]

I’m open to suggestions on how to better handle this. A Symbol cannot really be properly stringified as it doesn’t have any value. Even if you give two symbols the same description, per definition, they are supposed to be unique, but there’s no way (as far as I know) for us to stringify them as unique values. A regex could be handled somehow though, since it can be stringified with .toString(). So maybe if instead of JSON.stringifying the whole arguments object, we stringify each item and also include its type and also specially handle regex? That would still not solve the Symbol case.

// @maxwellgerber @keithamus @LinusU