enh(index.d.ts,index.ts): export getFIATValue & enhance type docs

Author: D3Portillo

lib/index.d.ts

@@ -39,13 +39,16 @@ export function useMetamask(
 ): UseMatamaskAPI
 /**
  * Fetch token price in USD,JPY & EUR from CoinGecko public api
- * @param coinGeckoID API ID, like `bitcoin`
+ * @param coinGeckoID API ID, like "bitcoin"
  * @returns [{ usd, jpy, eur }, triggerReFetchFn]
+ * @example
+ * const [btcPrice, reFetchFn] = useTokenPrice("bitcoin")
+ * console.log(btcPrice.usd) // Math.random() * 45_000
  */
 export function useTokenPrice(
   coinGeckoID: string,
   refreshInternvalInSecs?: number
-): [FIATCurrencies, /** Triggers a re-fetch to the API */ VoidCallback]
+): [FIATCurrencies, VoidCallback]
 export function addEtherNetwork(props: AddEtherNetwork): Promise<null>
 export function addEtherToken(props: AddEtherToken): Promise<null>
 export function getMetamaskProvider(): Metamask | null
@@ -58,9 +61,21 @@ export function switchOrAppendNetwork(props: AddEtherNetwork): Promise<null>
 export function sendEther(props: SendMethodProps): Promise<string>
 export function connectToMetamask(): Promise<string>
 export function formatEther(balance: number): string
-export function getFIATBalance(
+/**
+ * Returns a formatted string with a token FIAT value
+ * @param tokenBalance The amount of tokens to calculate
+ * @param tokenPrice The current token price per unit
+ * @param currency The currency token price is matched to
+ * @example
+ * const amount = 12
+ * const priceInUSD = 200
+ * const formattedValue = getFIATValue(amount, priceInUSD) // "2,400"
+ */
+export function getFIATValue(
   tokenBalance: number | string,
-  tokenPrice: number
-): number
+  tokenPrice: number | string,
+  /** Define a currency for `tokenPrice`. Defaults to "USD" */
+  currency?: "USD" | "JPY" | "EUR"
+): string
 export const metamaskRequest: OnRequest["request"]
 export const parse: Parse

lib/index.ts

@@ -10,6 +10,6 @@ export {
   sendEther,
   parse,
   connectToMetamask,
-  getFIATBalance,
+  getFIATValue,
   formatEther,
 } from "./utils"

lib/utils/index.ts

@@ -6,7 +6,7 @@ import internals from "./internals"
 const { withError, runIfMetamask, switchNetwork } = internals
 
 export { default as parse } from "./parse"
-
+export { default as getFIATValue } from "./getFIATValue"
 export const getMetamaskProvider = internals.getMetamaskProvider
 
 export const addEtherToken = ({
@@ -135,10 +135,12 @@ export const connectToMetamask = () => {
 }
 
 export const formatEther = (balance: number) => {
-  const result = balance < 0 ? balance.toPrecision(2) : balance.toFixed(3)
-  return `${parseFloat(result)}`
-}
-
-export const getFIATBalance = (balance, price) => {
-  return parseFloat((balance * price).toFixed(2))
+  const min = 1e-4
+  if (balance < min && balance > 0) {
+    return `${min}`
+  }
+  if (balance < 1) {
+    return `${balance}`
+  }
+  return `${parseFloat(balance.toFixed(4))}`
 }