Run results for: Test UUID with more optimizations

Test name	Executions per second
1	32253.5 Ops/sec
2	303850.8 Ops/sec
3	212333.6 Ops/sec
4	34834.6 Ops/sec
5	182836.6 Ops/sec
6	72253.9 Ops/sec
7	47957.5 Ops/sec
8	52422.1 Ops/sec

1

const generateUUID = () =>
    ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, e =>
        // eslint-disable-next-line no-bitwise
        (e ^ ((window.crypto || window.msCrypto).getRandomValues(new Uint8Array(1))[0] & (15 >> (e / 4)))).toString(16)
    );


generateUUID();

2

 function uuid() {
    let uuid = "",
        i,
        random;
    for (i = 0; i < 32; i++) {
        random = (Math.random() * 16) | 0;

        if (i == 8 || i == 12 || i == 16 || i == 20) {
            uuid += "-";
        }
        uuid += (i == 12 ? 4 : i == 16 ? (random & 3) | 8 : random).toString(16);
    }
    return uuid;
}

uuid();

3

 function uuid1(a) {
    return a
        ? (a ^ ((Math.random() * 16) >> (a / 4))).toString(16)
        : ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, uuid1);
}

uuid1()

4

var IDX=256, HEX=[], BUFFER;
while (IDX--) HEX[IDX] = (IDX + 256).toString(16).substring(1);


function v4() {
	var i=0, num, out='';

	if (!BUFFER || ((IDX + 16) > 256)) {
		BUFFER = Array(i=256);
		while (i--) BUFFER[i] = 256 * Math.random() | 0;
		i = IDX = 0;
	}

	for (; i < 16; i++) {
		num = BUFFER[IDX + i];
		if (i==6) out += HEX[num & 15 | 64];
		else if (i==8) out += HEX[num & 63 | 128];
		else out += HEX[num];

		if (i & 1 && i > 1 && i < 11) out += '-';
	}

	IDX++;
	return out;
}

v4();

5

const ui8a = new Uint8Array(1);
var IDX=256, HEX=[], BUFFER = Array(IDX);
while (IDX--) HEX[IDX] = (IDX + 256).toString(16).substring(1);


function v4() {
	var i=0, num, out='';

	if ((IDX + 16) > 256) {
		while (i--) BUFFER[i] = 256 * crypto.getRandomValues(ui8a)[0] | 0;
		i = IDX = 0;
	}

	for (; i < 16; i++) {
		num = BUFFER[IDX + i];
		if (i==6) out += HEX[num & 15 | 64];
		else if (i==8) out += HEX[num & 63 | 128];
		else out += HEX[num];

		if (i & 1 && i > 1 && i < 11) out += '-';
	}

	IDX++;
	return out;
}

v4();

6

const ui8a = new Uint8Array(1);
 function uuid() {
    let uuid = "",
        i,
        random;
    for (i = 0; i < 32; i++) {
        random = (crypto.getRandomValues(ui8a)[0] * 16) | 0;

        if (i == 8 || i == 12 || i == 16 || i == 20) {
            uuid += "-";
        }
        uuid += (i == 12 ? 4 : i == 16 ? (random & 3) | 8 : random).toString(16);
    }
    return uuid;
}

uuid();

7

const ui8a = new Uint8Array(1);
 function uuid() {
    let uuid = "00000000-000-000-000-00000000000",
        i,
        random;
    for (i = 0; i < 32; i++) {
        random = (crypto.getRandomValues(ui8a)[0] * 16) | 0;

        if (i === 8 || i === 12 || i === 16 || i === 20) continue;
        uuid[i] = (i == 12 ? 4 : i == 16 ? (random & 3) | 8 : random).toString(16);
    }
    return uuid;
}

uuid();

8

const ui8a = new Uint8Array(1);
 function uuid() {
    let uuid = "00000000-000-000-000-00000000000",
        i = 0,
        random;
   while(i < 32) {
     if (i === 8 || i === 12 || i === 16 || i === 20) {
     } else {
	   random = (crypto.getRandomValues(ui8a)[0] * 16) | 0;
       uuid[i] = (i === 12 ? 4 : i === 16 ? (random & 3) | 8 : random).toString(16);
     }
     i++;
   }
    return uuid;
}

uuid();