the similarity is not expected

[zkeen]

TEST 1:
let a = 'the cat sat on the mat'
let b = 'the cat sat on a mat'
let h1 = simhash.hash(a)
let h2 = simhash.hash(b)
console.log(h1, h2, sjs.Comparator.similarity(h1, h2))
// ------------ result
// 687990018 690349194 0.16666666666666666

TEST2:
let a = 'the cat sat on the mat'
let b = 'xxx xxxxxx xx xxx xxx'
let h1 = simhash.hash(a)
let h2 = simhash.hash(b)
console.log(h1, h2, sjs.Comparator.similarity(h1, h2))
// -------------- result
// 687990018 236331081 0.23529411764705882