How to convert big number to normal number?

Question

I am new to testing and I want to know how to convert a big number to a real number.

I use bignumber in the following command:

console.log(await this.crowdsale.rate());

This is what gets printed in the terminal:

BigNumber { s: 1, e: 2, c: [ 500 ] }

Answer 1

It depends what you mean by real number. You can check out here the divisions used in Ethereum.

For wei:

let bigNo = await this.crowdsale.rate();
console.log(bigNo.toNumber());

For ether add this:

console.log(web3.fromWei(bigNo.toNumber()));

If you're using version ^1.0.0 of web3, use web3.utils.fromWei instead of web3.fromWei.

Answer 2

Not every BigNumber can be converted into a Javascript Number with an equivalent value.

If that had been the case, then we wouldn't have needed a BigNumber class to begin with.

Referring to your actual question - you haven't really explained why you need to perform this conversion.

Your question implies that you don't like the printout, in which case you can fix your code as follows:

let rate = await this.crowdsale.rate();
console.log(rate.toFixed());

If you're interested in performing additional calculations, then you can simply use BigNumber functions.

So technically speaking, there shouldn't be any need convert your BigNumber into a Javascript Number.