Ethval NPM | npm.io

ethval

Easier calculation and formatting of Ethereum values.

Supports floating point numbers
Easily convert between Wei, Gwei and Eth
Output binary, decimal and hexadecimal strings
Output fixed-precision floating-point values (toFixed())
Parse and generate BN.js instances
Uses decimal.js under the hood

Install

NPM/Yarn: ethval

Example Usage

You can feed it BN.js instances returned from web3:

const EthVal = require('ethval')

const balance = await web3.eth.getBalance(account) // returns BN.js instance

// assume balance is 20000000000000000 wei (=0.02eth)

console.log( new EthVal(balance).toEth().mul(2).toFixed(2) ) // "0.04"

Use it calculate the Wei/Gwei/Eth equivalent of a given value:

const v = new EthVal('1.234', 'eth')

console.log( b.toGwei().toString() ) // "1234000000"

You can also output hex and binary strings:

const v = new EthVal(255)

console.log( b.toString(16) ) // "0xff"
console.log( b.toString(2) ) // "11111111"

Basic arithmetic supported fully:

const v = new EthVal(255)
const b = await web3.eth.getBalance('0x...') // assume balance is 100 wei

console.log( v.div(5).add(b).mul(2).sub(2).toString(16) ) // 0x12c (= 300 in base-10)

Comparisons too:

const { toBN } = require('web3-utils')

const v = new EthVal(255)
const v2 = new EthVal('0.2', 'eth')

console.log( v2.lt(v) ) // false
console.log( v.gt(200) ) // true
console.log( v.lte(toBN('0xFFFF')) ) // true

It also ensures units are aligned when performing operations:

const v = new EthVal(25500)
const v2 = new EthVal('0.2', 'eth')

console.log( v2.gt(v) ) // true
console.log( v.add(v2).toString() ) // "200000000000025500"
console.log( v2.add(v).toString() ) // "0.2000000000000255"

API

new EthVal(input, unit = 'wei')

Constructs a new EthVal instance.

input - can be a Number, a string (in base-10 or base-16/hex format), another EthVal instance, or a BN instance.
unit - must be one of eth, gwei or wei (default).

.toWei()

Convert the value to its Wei equivalent and return a new EthVal instance.

.toGwei()

Convert the value to its Gwei equivalent and return a new EthVal instance.

.toEth()

Convert the value to its Eth equivalent and return a new EthVal instance.

.add(input)

Add input to this value and return a new EthVal instance.

input - same as for the EthVal constructor

.sub(input)

Subtract input from this value and return a new EthVal instance.

input - same as for the EthVal constructor

.mul(input)

Multiply input with this value and return a new EthVal instance.

input - same as for the EthVal constructor

.div(input)

Divide this value by input and return a new EthVal instance.

input - same as for the EthVal constructor

.round()

Round this value to the nearest integer (i.e 0 decimal places) and return a new EthVal instance.

.eq(input)

Get whether this value equals input. Returns true or false.

input - same as for the EthVal constructor

.lt(input)

Get whether this value is less than input. Returns true or false.

input - same as for the EthVal constructor

.lte(input)

Get whether this value is less than or equal to input. Returns true or false.

input - same as for the EthVal constructor

.gt(input)

Get whether this value is greater than input. Returns true or false.

input - same as for the EthVal constructor

.gte(input)

Get whether this value is greater than or equal to input. Returns true or false.

input - same as for the EthVal constructor

.toString(base)

Return string representation of this value according to the given number base. For example, if base is 2 then a binary string representation is returned, if 16 then a hexadecimal string representation is returned.