big numbers

Examples of creating big number types from and to uint, string, hex, and buffers.

Node.js

const BN = require('bn.js')
let bn = new BN(75)
console.log(bn.toString(10))
bn = new BN('75')
console.log(bn.toString(10))
bn = new BN(0x4b, 'hex')
console.log(bn.toString(10))
bn = new BN('4b', 'hex')
console.log(bn.toString(10))
bn = new BN(Buffer.from('4b', 'hex'))
console.log(bn.toString(10))
console.log(bn.toNumber(10))
console.log(bn.toString('hex'))
console.log(bn.toBuffer())
let bn2 = new BN(5)
let isEqual = bn.cmp(bn2) == 0
console.log(isEqual)
bn2 = new BN('4b', 'hex')
isEqual = bn.cmp(bn2) == 0
console.log(isEqual)

Output

75
75
75
75
75
75
4b
<Buffer 4b>
false
true

Go

package main
import (
    "encoding/hex"
    "fmt"
    "math/big"
)
func main() {
    bn := new(big.Int)
    bn.SetUint64(75)
    fmt.Println(bn.String())
    bn = new(big.Int)
    bn.SetString("75", 10)
    fmt.Println(bn.String())
    bn = new(big.Int)
    bn.SetUint64(0x4b)
    fmt.Println(bn.String())
    bn = new(big.Int)
    bn.SetString("4b", 16)
    fmt.Println(bn.String())
    bn = new(big.Int)
    bn.SetBytes([]byte{0x4b})
    fmt.Println(bn.String())
    fmt.Println(bn.Uint64())
    fmt.Println(hex.EncodeToString(bn.Bytes()))
    fmt.Println(bn.Bytes())
    bn2 := big.NewInt(5)
    isEqual := bn.Cmp(bn2) == 0
    fmt.Println(isEqual)
    bn2 = big.NewInt(75)
    isEqual = bn.Cmp(bn2) == 0
    fmt.Println(isEqual)
}

Output

75
75
75
75
75
75
4b
[75]
false
true