Uuid

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API Method - uuidV4

This function is used to generate a version 4 (random) UUID. The function is based on the uuid package.

Signature

export const uuidV4 = (): string

Returns

A version 4 UUID of the form xxxxxxxx-xxxx-4xxx-xxxx-xxxxxxxxxxxx

Example

console.log(web3.utils.uuidV4());
> "1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed"

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Underlying Logic

The uuidV4 function generates a set of 16 random bytes using the randomBytes function.

The 7th byte is then manipulated such that its high nibble (half-byte) is set to 4, which indicates a version 4 UUID. This is in accordance with Section 4.1.3 of the relevant specifications.

The 9th byte is then manipulated such that its high nibble is set to 8, which is a variant for version 4 UUIDs. This manipulation is in accordance with Section 4.4 of the relevant specifications.

Finally, the function transforms the resulting bytes into a hexadecimal string and formats it into the conventional UUID format of xxxxxxxx-xxxx-4xxx-yyyy-xxxxxxxxxxxx. Each 'x' is a random hexadecimal digit, 'y' is a hexadecimal digit from the manipulated 9th byte.

Make sure your linter is set to ignore the two explicit byte manipulations. This operation is intentional and necessary for the aforementioned functionality.