When creating an Application, it is useful to convert between user-friendly strings (usually displaying ether) and the machine-readable values that contracts and maths depend on (usually in wei).
For example, a Wallet may specify the balance in ether, and gas prices in gwei for the User Interface, but when sending a transaction, both must be specified in wei.
The parseUnits will parse a string representing ether, such as 1.1 into a BigNumber in wei, and is useful when a user types in a value, such as sending 1.1 ether.
The formatUnits will format a BigNumberish into a string, which is useful when displaying a balance.
A Unit can be specified as an number, which indicates the number of decimal places that should be used.
Examples:
- 1 ether in wei, has 18 decimal places (i.e. 1 ether represents 1018 wei)
- 1 bitcoin in Satoshi, has 8 decimal places (i.e. 1 bitcoin represents 108 satoshi)
There are also several common Named Units, in which case their name (as a string) may be used.
| Name | Decimals | |
| wei | 0 | |
| kwei | 3 | |
| mwei | 6 | |
| gwei | 9 | |
| szabo | 12 | |
| finney | 15 | |
| ether | 18 |
Returns a string with value grouped by 3 digits, separated by ,.
Returns a string representation of value formatted with unit digits (if it is a number) or to the unit specified (if a string).
The equivalent to calling formatUnits(value, "ether").
Returns a BigNumber representation of value, parsed with unit digits (if it is a number) or from the unit specified (if a string).
The equivalent to calling parseUnits(value, "ether").