.. _utils: .. include:: include_announcement.rst ========== web3.utils ========== This package provides utility functions for Ethereum dapps and other web3.js packages. ------------------------------------------------------------------------------ randomHex ===================== .. code-block:: javascript web3.utils.randomHex(size) The `randomHex `_ library to generate cryptographically strong pseudo-random HEX strings from a given byte size. ---------- Parameters ---------- 1. ``size`` - ``Number``: The byte size for the HEX string, e.g. ``32`` will result in a 32 bytes HEX string with 64 characters preficed with "0x". ------- Returns ------- ``String``: The generated random HEX string. ------- Example ------- .. code-block:: javascript web3.utils.randomHex(32) > "0xa5b9d60f32436310afebcfda832817a68921beb782fabf7915cc0460b443116a" web3.utils.randomHex(4) > "0x6892ffc6" web3.utils.randomHex(2) > "0x99d6" web3.utils.randomHex(1) > "0x9a" web3.utils.randomHex(0) > "0x" ------------------------------------------------------------------------------ .. _utils-bn: BN ===================== .. code-block:: javascript web3.utils.BN(mixed) The `BN.js `_ library for calculating with big numbers in JavaScript. See the `BN.js documentation `_ for details. .. note:: For safe conversion of many types, incl `BigNumber.js `_ use :ref:`utils.toBN ` ---------- Parameters ---------- 1. ``value`` - ``String|Number``: A number, number string or HEX string to convert to a BN object. ------- Returns ------- ``Object``: The `BN.js `_ instance. ------- Example ------- .. code-block:: javascript const BN = web3.utils.BN; new BN(1234).toString(); > "1234" new BN('1234').add(new BN('1')).toString(); > "1235" new BN('0xea').toString(); > "234" ------------------------------------------------------------------------------ isBN ===================== .. code-block:: javascript web3.utils.isBN(bn) Checks if a given value is a `BN.js `_ instance. ---------- Parameters ---------- 1. ``bn`` - ``Object``: An `BN.js `_ instance. ------- Returns ------- ``Boolean`` ------- Example ------- .. code-block:: javascript const number = new BN(10); web3.utils.isBN(number); > true ------------------------------------------------------------------------------ isBigNumber ===================== .. code-block:: javascript web3.utils.isBigNumber(bignumber) Checks if a given value is a `BigNumber.js `_ instance. ---------- Parameters ---------- 1. ``BigNumber`` - ``Object``: A `BigNumber.js `_ instance. ------- Returns ------- ``Boolean`` ------- Example ------- .. code-block:: javascript const number = new BigNumber(10); web3.utils.isBigNumber(number); > true ------------------------------------------------------------------------------ keccak256 ===================== .. code-block:: javascript web3.utils.keccak256(string) web3.utils.sha3(string) // ALIAS Will calculate the keccak256 of the input. .. note:: To mimic the keccak256 behaviour of solidity use :ref:`soliditySha3 ` ---------- Parameters ---------- 1. ``string`` - ``String``: A string to hash. ------- Returns ------- ``String``: the result hash. ------- Example ------- .. code-block:: javascript web3.utils.keccak256('234'); // taken as string > "0xc1912fee45d61c87cc5ea59dae311904cd86b84fee17cc96966216f811ce6a79" web3.utils.keccak256(new BN('234')); > "0xbc36789e7a1e281436464229828f817d6612f7b477d66591ff96a9e064bcc98a" web3.utils.keccak256(234); > null // can't calculate the hash of a number web3.utils.keccak256(0xea); // same as above, just the HEX representation of the number > null web3.utils.keccak256('0xea'); // will be converted to a byte array first, and then hashed > "0x2f20677459120677484f7104c76deb6846a2c071f9b3152c103bb12cd54d1a4a" ------------------------------------------------------------------------------ .. _utils-soliditysha3: soliditySha3 ===================== .. code-block:: javascript web3.utils.soliditySha3(param1 [, param2, ...]) Will calculate the sha3 of given input parameters in the same way solidity would. This means arguments will be ABI converted and tightly packed before being hashed. ---------- Parameters ---------- 1. ``paramX`` - ``Mixed``: Any type, or an object with ``{type: 'uint', value: '123456'}`` or ``{t: 'bytes', v: '0xfff456'}``. Basic types are autodetected as follows: - ``String`` non numerical UTF-8 string is interpreted as ``string``. - ``String|Number|BN|HEX`` positive number is interpreted as ``uint256``. - ``String|Number|BN`` negative number is interpreted as ``int256``. - ``Boolean`` as ``bool``. - ``String`` HEX string with leading ``0x`` is interpreted as ``bytes``. - ``HEX`` HEX number representation is interpreted as ``uint256``. ------- Returns ------- ``String``: the result hash. ------- Example ------- .. code-block:: javascript web3.utils.soliditySha3('234564535', '0xfff23243', true, -10); // auto detects: uint256, bytes, bool, int256 > "0x3e27a893dc40ef8a7f0841d96639de2f58a132be5ae466d40087a2cfa83b7179" web3.utils.soliditySha3('Hello!%'); // auto detects: string > "0x661136a4267dba9ccdf6bfddb7c00e714de936674c4bdb065a531cf1cb15c7fc" web3.utils.soliditySha3('234'); // auto detects: uint256 > "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2" web3.utils.soliditySha3(0xea); // same as above > "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2" web3.utils.soliditySha3(new BN('234')); // same as above > "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2" web3.utils.soliditySha3({type: 'uint256', value: '234'})); // same as above > "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2" web3.utils.soliditySha3({t: 'uint', v: new BN('234')})); // same as above > "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2" web3.utils.soliditySha3('0x407D73d8a49eeb85D32Cf465507dd71d507100c1'); > "0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b" web3.utils.soliditySha3({t: 'bytes', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'}); > "0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b" // same result as above web3.utils.soliditySha3({t: 'address', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'}); > "0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b" // same as above, but will do a checksum check, if its multi case web3.utils.soliditySha3({t: 'bytes32', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'}); > "0x3c69a194aaf415ba5d6afca734660d0a3d45acdc05d54cd1ca89a8988e7625b4" // different result as above web3.utils.soliditySha3({t: 'string', v: 'Hello!%'}, {t: 'int8', v:-23}, {t: 'address', v: '0x85F43D8a49eeB85d32Cf465507DD71d507100C1d'}); > "0xa13b31627c1ed7aaded5aecec71baf02fe123797fffd45e662eac8e06fbe4955" ------------------------------------------------------------------------------ isHex ===================== .. code-block:: javascript web3.utils.isHex(hex) Checks if a given string is a HEX string. ---------- Parameters ---------- 1. ``hex`` - ``String|HEX``: The given HEX string. ------- Returns ------- ``Boolean`` ------- Example ------- .. code-block:: javascript web3.utils.isHex('0xc1912'); > true web3.utils.isHex(0xc1912); > true web3.utils.isHex('c1912'); > true web3.utils.isHex(345); > true // this is tricky, as 345 can be a a HEX representation or a number, be careful when not having a 0x in front! web3.utils.isHex('0xZ1912'); > false web3.utils.isHex('Hello'); > false ------------------------------------------------------------------------------ isHexStrict ===================== .. code-block:: javascript web3.utils.isHexStrict(hex) Checks if a given string is a HEX string. Difference to ``web3.utils.isHex()`` is that it expects HEX to be prefixed with ``0x``. ---------- Parameters ---------- 1. ``hex`` - ``String|HEX``: The given HEX string. ------- Returns ------- ``Boolean`` ------- Example ------- .. code-block:: javascript web3.utils.isHexStrict('0xc1912'); > true web3.utils.isHexStrict(0xc1912); > false web3.utils.isHexStrict('c1912'); > false web3.utils.isHexStrict(345); > false // this is tricky, as 345 can be a a HEX representation or a number, be careful when not having a 0x in front! web3.utils.isHexStrict('0xZ1912'); > false web3.utils.isHex('Hello'); > false ------------------------------------------------------------------------------ isAddress ===================== .. code-block:: javascript web3.utils.isAddress(address, [, chainId]) Checks if a given string is a valid Ethereum address. It will also check the checksum, if the address has upper and lowercase letters. ---------- Parameters ---------- 1. ``address`` - ``String``: An address string. 2. ``chainId`` - ``number`` (optional): Chain id where checksummed address should be valid, defaults to ``null``. RSKIP-60 for details. ------- Returns ------- ``Boolean`` ------- Example ------- .. code-block:: javascript web3.utils.isAddress('0xc1912fee45d61c87cc5ea59dae31190fffff232d'); > true web3.utils.isAddress('c1912fee45d61c87cc5ea59dae31190fffff232d'); > true web3.utils.isAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D'); > true // as all is uppercase, no checksum will be checked web3.utils.isAddress('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d'); > true web3.utils.isAddress('0xC1912fEE45d61C87Cc5EA59DaE31190FFFFf232d'); > false // wrong checksum web3.utils.isAddress('0x5aaEB6053f3e94c9b9a09f33669435E7ef1bEAeD', 30); > true ------------------------------------------------------------------------------ toChecksumAddress ================= .. code-block:: javascript web3.utils.toChecksumAddress(address[, chainId]) Will convert an upper or lowercase Ethereum address to a checksum address. ---------- Parameters ---------- 1. ``address`` - ``String``: An address string. 2. ``chainId`` - ``number`` (optional): Chain id where checksummed address should be valid, defaults to ``null``. RSKIP-60 for details. ------- Returns ------- ``String``: The checksum address. ------- Example ------- .. code-block:: javascript web3.utils.toChecksumAddress('0xc1912fee45d61c87cc5ea59dae31190fffff2323'); > "0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d" web3.utils.toChecksumAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D'); > "0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d" // same as above web3.utils.toChecksumAddress('0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed', 30); > "0x5aaEB6053f3e94c9b9a09f33669435E7ef1bEAeD" ------------------------------------------------------------------------------ stripHexPrefix ============== .. code-block:: javascript web3.utils.stripHexPrefix(address) Removes the prefix ``0x`` from a given hex if it exists. ---------- Parameters ---------- 1. ``hex`` - ``String``: Hex ------- Returns ------- ``String``: Hex without prefix. ------- Example ------- .. code-block:: javascript web3.utils.stripHexPrefix('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d'); > "c1912fEE45d61C87Cc5EA59DaE31190FFFFf232d" ------------------------------------------------------------------------------ checkAddressChecksum ==================== .. code-block:: javascript web3.utils.checkAddressChecksum(address [, chainId]) Checks the checksum of a given address. Will also return false on non-checksum addresses. ---------- Parameters ---------- 1. ``address`` - ``String``: An address string. 2. ``chainId`` - ``number`` (optional): Chain id where checksummed address should be valid, defaults to ``null``. RSKIP-60 for details. ------- Returns ------- ``Boolean``: ``true`` when the checksum of the address is valid, ``false`` if its not a checksum address, or the checksum is invalid. ------- Example ------- .. code-block:: javascript web3.utils.checkAddressChecksum('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d'); > true web3.utils.checkAddressChecksum('0x5aAeb6053F3e94c9b9A09F33669435E7EF1BEaEd', 31); > true ------------------------------------------------------------------------------ toHex ===================== .. code-block:: javascript web3.utils.toHex(mixed) Will auto convert any given value to HEX. Number strings will interpreted as numbers. Text strings will be interpreted as UTF-8 strings. ---------- Parameters ---------- 1. ``value`` - ``String|Number|BN|BigNumber``: The input to convert to HEX. ------- Returns ------- ``String``: The resulting HEX string. ------- Example ------- .. code-block:: javascript web3.utils.toHex('234'); > "0xea" web3.utils.toHex(234); > "0xea" web3.utils.toHex(new BN('234')); > "0xea" web3.utils.toHex(new BigNumber('234')); > "0xea" web3.utils.toHex('I have 100€'); > "0x49206861766520313030e282ac" ------------------------------------------------------------------------------ .. _utils-tobn: toBN ===================== .. code-block:: javascript web3.utils.toBN(number) Will safely convert any given value (including `BigNumber.js `_ instances) into a `BN.js `_ instance, for handling big numbers in JavaScript. .. note:: For just the `BN.js `_ class use :ref:`utils.BN ` ---------- Parameters ---------- 1. ``number`` - ``String|Number|HEX``: Number to convert to a big number. ------- Returns ------- ``Object``: The `BN.js `_ instance. ------- Example ------- .. code-block:: javascript web3.utils.toBN(1234).toString(); > "1234" web3.utils.toBN('1234').add(web3.utils.toBN('1')).toString(); > "1235" web3.utils.toBN('0xea').toString(); > "234" ------------------------------------------------------------------------------ hexToNumberString ===================== .. code-block:: javascript web3.utils.hexToNumberString(hex) Returns the number representation of a given HEX value as a string. ---------- Parameters ---------- 1. ``hexString`` - ``String|HEX``: A string to hash. ------- Returns ------- ``String``: The number as a string. ------- Example ------- .. code-block:: javascript web3.utils.hexToNumberString('0xea'); > "234" ------------------------------------------------------------------------------ hexToNumber ===================== .. code-block:: javascript web3.utils.hexToNumber(hex) web3.utils.toDecimal(hex) // ALIAS, deprecated Returns the number representation of a given HEX value. .. note:: This is not useful for big numbers, rather use :ref:`utils.toBN ` instead. ---------- Parameters ---------- 1. ``hexString`` - ``String|HEX``: A string to hash. ------- Returns ------- ``Number`` ------- Example ------- .. code-block:: javascript web3.utils.hexToNumber('0xea'); > 234 ------------------------------------------------------------------------------ numberToHex ===================== .. code-block:: javascript web3.utils.numberToHex(number) web3.utils.fromDecimal(number) // ALIAS, deprecated Returns the HEX representation of a given number value. ---------- Parameters ---------- 1. ``number`` - ``String|Number|BN|BigNumber``: A number as string or number. ------- Returns ------- ``String``: The HEX value of the given number. ------- Example ------- .. code-block:: javascript web3.utils.numberToHex('234'); > '0xea' ------------------------------------------------------------------------------ hexToUtf8 ===================== .. code-block:: javascript web3.utils.hexToUtf8(hex) web3.utils.hexToString(hex) // ALIAS web3.utils.toUtf8(hex) // ALIAS, deprecated Returns the UTF-8 string representation of a given HEX value. ---------- Parameters ---------- 1. ``hex`` - ``String``: A HEX string to convert to a UTF-8 string. ------- Returns ------- ``String``: The UTF-8 string. ------- Example ------- .. code-block:: javascript web3.utils.hexToUtf8('0x49206861766520313030e282ac'); > "I have 100€" ------------------------------------------------------------------------------ hexToAscii ===================== .. code-block:: javascript web3.utils.hexToAscii(hex) web3.utils.toAscii(hex) // ALIAS, deprecated Returns the ASCII string representation of a given HEX value. ---------- Parameters ---------- 1. ``hex`` - ``String``: A HEX string to convert to a ASCII string. ------- Returns ------- ``String``: The ASCII string. ------- Example ------- .. code-block:: javascript web3.utils.hexToAscii('0x4920686176652031303021'); > "I have 100!" ------------------------------------------------------------------------------ .. _utils-utf8tohex: utf8ToHex ===================== .. code-block:: javascript web3.utils.utf8ToHex(string) web3.utils.stringToHex(string) // ALIAS web3.utils.fromUtf8(string) // ALIAS, deprecated Returns the HEX representation of a given UTF-8 string. ---------- Parameters ---------- 1. ``string`` - ``String``: A UTF-8 string to convert to a HEX string. ------- Returns ------- ``String``: The HEX string. ------- Example ------- .. code-block:: javascript web3.utils.utf8ToHex('I have 100€'); > "0x49206861766520313030e282ac" ------------------------------------------------------------------------------ asciiToHex ===================== .. code-block:: javascript web3.utils.asciiToHex(string) web3.utils.fromAscii(string) // ALIAS, deprecated Returns the HEX representation of a given ASCII string. If you would like to transform an ASCII string into a valid ``bytes4``, ``bytes8`` etc. value then please pass the correct length as the second parameter. ---------- Parameters ---------- 1. ``string`` - ``String``: A ASCII string to convert to a HEX string. 2. ``length`` - ``Number``: The length of the returned hex string. The default size is ``32`` e.g.: ``bytes32``. ------- Returns ------- ``String``: The HEX string. ------- Example ------- .. code-block:: javascript web3.utils.asciiToHex('I have 100!'); > "0x4920686176652031303021000000000000000000000000000000000000000000" // transforming to a bytes4 value: web3.utils.asciiToHex('yes', 4); // transforming to a bytes8 value: web3.utils.asciiToHex('yes', 8); //etc. ------------------------------------------------------------------------------ hexToBytes ===================== .. code-block:: javascript web3.utils.hexToBytes(hex) Returns a byte array from the given HEX string. ---------- Parameters ---------- 1. ``hex`` - ``String|HEX``: A HEX to convert. ------- Returns ------- ``Array``: The byte array. ------- Example ------- .. code-block:: javascript web3.utils.hexToBytes('0x000000ea'); > [ 0, 0, 0, 234 ] web3.utils.hexToBytes(0x000000ea); > [ 234 ] ------------------------------------------------------------------------------ bytesToHex ===================== .. code-block:: javascript web3.utils.bytesToHex(byteArray) Returns a HEX string from a byte array. ---------- Parameters ---------- 1. ``byteArray`` - ``Array``: A byte array to convert. ------- Returns ------- ``String``: The HEX string. ------- Example ------- .. code-block:: javascript web3.utils.bytesToHex([ 72, 101, 108, 108, 111, 33, 36 ]); > "0x48656c6c6f2125" ------------------------------------------------------------------------------ toWei ===================== .. code-block:: javascript web3.utils.toWei(number [, unit]) Converts any `ether value `_ value into `wei `_. .. note:: "wei" are the smallest ethere unit, and you should always make calculations in wei and convert only for display reasons. ---------- Parameters ---------- 1. ``number`` - ``String|BN``: The value. 2. ``unit`` - ``String`` (optional, defaults to ``"ether"``): The ether to convert from. Possible units are: - ``noether``: '0' - ``wei``: '1' - ``kwei``: '1000' - ``Kwei``: '1000' - ``babbage``: '1000' - ``femtoether``: '1000' - ``mwei``: '1000000' - ``Mwei``: '1000000' - ``lovelace``: '1000000' - ``picoether``: '1000000' - ``gwei``: '1000000000' - ``Gwei``: '1000000000' - ``shannon``: '1000000000' - ``nanoether``: '1000000000' - ``nano``: '1000000000' - ``szabo``: '1000000000000' - ``microether``: '1000000000000' - ``micro``: '1000000000000' - ``finney``: '1000000000000000' - ``milliether``: '1000000000000000' - ``milli``: '1000000000000000' - ``ether``: '1000000000000000000' - ``kether``: '1000000000000000000000' - ``grand``: '1000000000000000000000' - ``mether``: '1000000000000000000000000' - ``gether``: '1000000000000000000000000000' - ``tether``: '1000000000000000000000000000000' ------- Returns ------- ``String|BN``: If a string is given it returns a number string, otherwise a `BN.js `_ instance. ------- Example ------- .. code-block:: javascript web3.utils.toWei('1', 'ether'); > "1000000000000000000" web3.utils.toWei('1', 'finney'); > "1000000000000000" web3.utils.toWei('1', 'szabo'); > "1000000000000" web3.utils.toWei('1', 'shannon'); > "1000000000" ------------------------------------------------------------------------------ fromWei ===================== .. code-block:: javascript web3.utils.fromWei(number [, unit]) Converts any `wei `_ value into a `ether value `_. .. note:: "wei" are the smallest ethere unit, and you should always make calculations in wei and convert only for display reasons. ---------- Parameters ---------- 1. ``number`` - ``String|BN``: The value in wei. 2. ``unit`` - ``String`` (optional, defaults to ``"ether"``): The ether to convert to. Possible units are: - ``noether``: '0' - ``wei``: '1' - ``kwei``: '1000' - ``Kwei``: '1000' - ``babbage``: '1000' - ``femtoether``: '1000' - ``mwei``: '1000000' - ``Mwei``: '1000000' - ``lovelace``: '1000000' - ``picoether``: '1000000' - ``gwei``: '1000000000' - ``Gwei``: '1000000000' - ``shannon``: '1000000000' - ``nanoether``: '1000000000' - ``nano``: '1000000000' - ``szabo``: '1000000000000' - ``microether``: '1000000000000' - ``micro``: '1000000000000' - ``finney``: '1000000000000000' - ``milliether``: '1000000000000000' - ``milli``: '1000000000000000' - ``ether``: '1000000000000000000' - ``kether``: '1000000000000000000000' - ``grand``: '1000000000000000000000' - ``mether``: '1000000000000000000000000' - ``gether``: '1000000000000000000000000000' - ``tether``: '1000000000000000000000000000000' ------- Returns ------- ``String``: It always returns a string number. ------- Example ------- .. code-block:: javascript web3.utils.fromWei('1', 'ether'); > "0.000000000000000001" web3.utils.fromWei('1', 'finney'); > "0.000000000000001" web3.utils.fromWei('1', 'szabo'); > "0.000000000001" web3.utils.fromWei('1', 'shannon'); > "0.000000001" ------------------------------------------------------------------------------ unitMap ===================== .. code-block:: javascript web3.utils.unitMap Shows all possible `ether value `_ and their amount in `wei `_. ---------- Return value ---------- - ``Object`` with the following properties: - ``noether``: '0' - ``wei``: '1' - ``kwei``: '1000' - ``Kwei``: '1000' - ``babbage``: '1000' - ``femtoether``: '1000' - ``mwei``: '1000000' - ``Mwei``: '1000000' - ``lovelace``: '1000000' - ``picoether``: '1000000' - ``gwei``: '1000000000' - ``Gwei``: '1000000000' - ``shannon``: '1000000000' - ``nanoether``: '1000000000' - ``nano``: '1000000000' - ``szabo``: '1000000000000' - ``microether``: '1000000000000' - ``micro``: '1000000000000' - ``finney``: '1000000000000000' - ``milliether``: '1000000000000000' - ``milli``: '1000000000000000' - ``ether``: '1000000000000000000' - ``kether``: '1000000000000000000000' - ``grand``: '1000000000000000000000' - ``mether``: '1000000000000000000000000' - ``gether``: '1000000000000000000000000000' - ``tether``: '1000000000000000000000000000000' ------- Example ------- .. code-block:: javascript web3.utils.unitMap > { noether: '0', wei: '1', kwei: '1000', Kwei: '1000', babbage: '1000', femtoether: '1000', mwei: '1000000', Mwei: '1000000', lovelace: '1000000', picoether: '1000000', gwei: '1000000000', Gwei: '1000000000', shannon: '1000000000', nanoether: '1000000000', nano: '1000000000', szabo: '1000000000000', microether: '1000000000000', micro: '1000000000000', finney: '1000000000000000', milliether: '1000000000000000', milli: '1000000000000000', ether: '1000000000000000000', kether: '1000000000000000000000', grand: '1000000000000000000000', mether: '1000000000000000000000000', gether: '1000000000000000000000000000', tether: '1000000000000000000000000000000' } ------------------------------------------------------------------------------ padLeft ===================== .. code-block:: javascript web3.utils.padLeft(string, characterAmount [, sign]) web3.utils.leftPad(string, characterAmount [, sign]) // ALIAS Adds a padding on the left of a string, Useful for adding paddings to HEX strings. ---------- Parameters ---------- 1. ``string`` - ``String``: The string to add padding on the left. 2. ``characterAmount`` - ``Number``: The number of characters the total string should have. 3. ``sign`` - ``String`` (optional): The character sign to use, defaults to ``"0"``. ------- Returns ------- ``String``: The padded string. ------- Example ------- .. code-block:: javascript web3.utils.padLeft('0x3456ff', 20); > "0x000000000000003456ff" web3.utils.padLeft(0x3456ff, 20); > "0x000000000000003456ff" web3.utils.padLeft('Hello', 20, 'x'); > "xxxxxxxxxxxxxxxHello" ------------------------------------------------------------------------------ padRight ===================== .. code-block:: javascript web3.utils.padRight(string, characterAmount [, sign]) web3.utils.rightPad(string, characterAmount [, sign]) // ALIAS Adds a padding on the right of a string, Useful for adding paddings to HEX strings. ---------- Parameters ---------- 1. ``string`` - ``String``: The string to add padding on the right. 2. ``characterAmount`` - ``Number``: The number of characters the total string should have. 3. ``sign`` - ``String`` (optional): The character sign to use, defaults to ``"0"``. ------- Returns ------- ``String``: The padded string. ------- Example ------- .. code-block:: javascript web3.utils.padRight('0x3456ff', 20); > "0x3456ff00000000000000" web3.utils.padRight(0x3456ff, 20); > "0x3456ff00000000000000" web3.utils.padRight('Hello', 20, 'x'); > "Helloxxxxxxxxxxxxxxx" ------------------------------------------------------------------------------ toTwosComplement ===================== .. code-block:: javascript web3.utils.toTwosComplement(number) Converts a negative numer into a two's complement. ---------- Parameters ---------- 1. ``number`` - ``Number|String|BigNumber``: The number to convert. ------- Returns ------- ``String``: The converted hex string. ------- Example ------- .. code-block:: javascript web3.utils.toTwosComplement('-1'); > "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" web3.utils.toTwosComplement(-1); > "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" web3.utils.toTwosComplement('0x1'); > "0x0000000000000000000000000000000000000000000000000000000000000001" web3.utils.toTwosComplement(-15); > "0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff1" web3.utils.toTwosComplement('-0x1'); > "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" ------------------------------------------------------------------------------ getSignatureParameters ====================== .. code-block:: javascript web3.utils.getSignatureParameters(string) Gets the r, s and v values of an ECDSA signature ---------- Parameters ---------- 1. ``string`` - ``String``: An ECDSA signature. ------- Returns ------- ``Object``: Object containing r,s,v values. ------- Example ------- .. code-block:: javascript web3.utils.getSignatureParameters('0x5763ab346198e3e6cc4d53996ccdeca0c941cb6cb70d671d97711c421d3bf7922c77ef244ad40e5262d1721bf9638fb06bab8ed3c43bfaa80d6da0be9bbd33dc1b'); > "{ r: '0x5763ab346198e3e6cc4d53996ccdeca0c941cb6cb70d671d97711c421d3bf792', s: '0x2c77ef244ad40e5262d1721bf9638fb06bab8ed3c43bfaa80d6da0be9bbd33dc', v: 27 }"