How to set asterix in eq()

Hi everyone,
I want to do something like:

const category: string = '*'???

client.from('table').select('*').eq('category', category)

const category: string = '*'???

client.from('table').select('*').eq('category', category)

const category: string = '*'???

client.from('table').select('*').eq('category', category)

const category: string = '*'???

client.from('table').select('*').eq('category', category)

So If I set a value for 'category' it will filter accordingly, if not it will give back all (or basically ignore the filter).

Thanks!