sfc32 random number generator, typescript

sfc32.ts

// SFC32 random number generator, public domain code adapted
// from https://github.com/bryc/code/blob/master/jshash/PRNGs.md
function PRNG(seed: number): {
    nextInt(): number;
    nextFloat(): number;
    getState(): number[];
    setState(state: number[]): void
} {
    let a = 0, b = seed, c = 0, d = 1;
    function sfc32() {
        a |= 0; b |= 0; c |= 0; d |= 0; 
        var t = (a + b | 0) + d | 0;
        d = d + 1 | 0;
        a = b ^ b >>> 9;
        b = c + (c << 3) | 0;
        c = c << 21 | c >>> 11;
        c = c + t | 0;
        return t >>> 0;
    };
    for (let i = 0; i < 12; i++) sfc32(); // scramble the seed
    return {
        nextInt: sfc32,
        nextFloat() { return sfc32() / 4294967296; },
        getState() { return [a, b, c, d]; },
        setState(state: number[]) { [a, b, c, d] = state; },
    };
}