javascript - How ~(tilde)Infinity becomes -1

Question

~Infinity my question is how it evaluate to -1.

~Infinity= -1

console.log(~Infinity);

Answer 1

In IEEE 754 floating point, the Infinity constant is represented by a value with all the fraction bits set to 0. When that's coerced to a 32-bit integer value in calculating the bitwise complement (the ~ unary operator), you get just zero, so the complement is all 1 bits, or -1.

Positive infinity is:

01111111111100000000000000000000000000000000000000000000000000000

(give or take a zero). The sign bit is 0, the exponent is all 1 bits, and the mantissa is all zeros.