diff --git a/README.md b/README.md
index 4a560d7..5419368 100755
--- a/README.md
+++ b/README.md
@@ -38,6 +38,8 @@ $ yarn add react-currency-hooks
 import { useCurrency } from 'react-currency-hooks';
 ```
 
+<!-- TODO update docs -->
+
 #### Params
 
 | Name        | Type   | Default | Description                |
diff --git a/__tests__/useCurrency.test.ts b/__tests__/useCurrency.test.ts
index bca070f..8ea48de 100644
--- a/__tests__/useCurrency.test.ts
+++ b/__tests__/useCurrency.test.ts
@@ -2,6 +2,8 @@ import { renderHook } from '@testing-library/react-hooks';
 
 import { useCurrency } from '../src';
 
+// TODO test different amount
+// TODO test root options
 describe('useCurrency', () => {
   const rates = {
     GBP: 0.92,
@@ -18,9 +20,9 @@ describe('useCurrency', () => {
       rates,
     };
 
-    const { result } = renderHook(() => useCurrency(200, options));
+    const { result } = renderHook(() => useCurrency());
 
-    expect(result.current).toBe(192.85714285714286);
+    expect(result.current(200, options)).toBe(192.85714285714286);
   });
 
   it('should return 2 `to` values', () => {
@@ -31,9 +33,9 @@ describe('useCurrency', () => {
       rates,
     };
 
-    const { result } = renderHook(() => useCurrency(200, options));
+    const { result } = renderHook(() => useCurrency());
 
-    expect(result.current).toMatchObject({
+    expect(result.current(200, options)).toMatchObject({
       chf: 192.85714285714286,
       gbp: 164.28571428571428,
     });
@@ -48,9 +50,9 @@ describe('useCurrency', () => {
       keepPrecision: false,
     };
 
-    const { result } = renderHook(() => useCurrency(200, options));
+    const { result } = renderHook(() => useCurrency());
 
-    expect(result.current).toBe(192.86);
+    expect(result.current(200, options)).toBe(192.86);
   });
 
   it('should return single `to` value from hook with the same `base` and `from` rates', () => {
@@ -61,9 +63,9 @@ describe('useCurrency', () => {
       rates,
     };
 
-    const { result } = renderHook(() => useCurrency(200, options));
+    const { result } = renderHook(() => useCurrency());
 
-    expect(result.current).toBe(216);
+    expect(result.current(200, options)).toBe(216);
   });
 
   it('should return single `to` value from hook with the same `base` and `to` rates', () => {
@@ -74,9 +76,9 @@ describe('useCurrency', () => {
       rates,
     };
 
-    const { result } = renderHook(() => useCurrency(200, options));
+    const { result } = renderHook(() => useCurrency());
 
-    expect(result.current).toBe(178.57142857142856);
+    expect(result.current(200, options)).toBe(178.57142857142856);
   });
 
   it('should return single `to` value from hook without `base` rate', () => {
@@ -87,9 +89,9 @@ describe('useCurrency', () => {
       rates,
     };
 
-    const { result } = renderHook(() => useCurrency(200, options));
+    const { result } = renderHook(() => useCurrency());
 
-    expect(result.current).toBe(192.85714285714286);
+    expect(result.current(200, options)).toBe(192.85714285714286);
   });
 
   it('should return an error', () => {
@@ -101,7 +103,9 @@ describe('useCurrency', () => {
         rates,
       };
 
-      renderHook(() => useCurrency(200, options));
+      const { result } = renderHook(() => useCurrency());
+
+      result.current(200, options);
     } catch (err) {
       expect(err.message).toBe(
         '`rates` object does not contain either `from` or `to` currency!'
diff --git a/rollup.config.js b/rollup.config.js
index 0d80503..a86e78f 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -19,5 +19,5 @@ export default {
     },
   ],
   plugins: [resolve(), typescript(), terser()],
-  external: Object.keys(pkg.peerDependencies),
+  external: Object.keys(pkg.peerDependencies || {}), // TODO add fallback for dependencies
 };
diff --git a/src/useCurrency.ts b/src/useCurrency.ts
index dab07c6..2ac7700 100644
--- a/src/useCurrency.ts
+++ b/src/useCurrency.ts
@@ -1,4 +1,4 @@
-import { useState, useEffect, useCallback } from 'react';
+import { useCallback } from 'react';
 
 import { hasKey } from './helpers/hasKey';
 
@@ -6,58 +6,61 @@ import { Options } from './interfaces/Options';
 
 import type { Rates } from './types/rates';
 
-export const useCurrency = (amount: number, options: Options) => {
-  const { from, to, base, rates, keepPrecision = true } = options;
+type ConvertCurrencyCallback = (
+  amount: number,
+  options?: Options
+) => number | Record<string, number> | undefined;
 
-  const [conversion, setConversion] = useState<number | Rates | undefined>(
-    to instanceof Array ? {} : undefined
-  );
+export const useCurrency = (rootOptions?: Options) => {
+  return useCallback<ConvertCurrencyCallback>(
+    (amount, options) => {
+      const { from, to, base, rates, keepPrecision = true } = {
+        ...rootOptions,
+        ...options,
+      };
 
-  const getRate = useCallback(
-    (to: string) => {
-      if (from === base && hasKey(rates, to)) {
-        return rates[to];
-      }
+      const getRate = (to: string) => {
+        if (from === base && hasKey(rates, to)) {
+          return rates[to];
+        }
 
-      if (to === base && hasKey(rates, from)) {
-        return 1 / rates[from];
-      }
+        if (to === base && hasKey(rates, from)) {
+          return 1 / rates[from];
+        }
 
-      if (hasKey(rates, from) && hasKey(rates, to)) {
-        return rates[to] * (1 / rates[from]);
-      }
+        if (hasKey(rates, from) && hasKey(rates, to)) {
+          return rates[to] * (1 / rates[from]);
+        }
 
-      throw new Error(
-        '`rates` object does not contain either `from` or `to` currency!'
-      );
-    },
-    [base, from, rates]
-  );
+        throw new Error(
+          '`rates` object does not contain either `from` or `to` currency!'
+        );
+      };
 
-  const convert = useCallback(
-    (to: string) => {
-      const convertedValue = amount * 100 * getRate(to);
+      // TODO rename function
+      const convert = (to: string) => {
+        const convertedValue = amount * 100 * getRate(to);
 
-      return (
-        (keepPrecision ? convertedValue : Math.round(convertedValue)) / 100
-      );
-    },
-    [amount, getRate, keepPrecision]
-  );
+        return (
+          (keepPrecision ? convertedValue : Math.round(convertedValue)) / 100
+        );
+      };
 
-  useEffect(() => {
-    if (to instanceof Array) {
-      const converted: Rates = {};
+      // TODO refactor
+      if (to instanceof Array) {
+        const converted: Rates = {};
 
-      to.map((currency) => {
-        converted[currency.toLowerCase()] = convert(currency);
-      });
+        to.map((currency) => {
+          converted[currency.toLowerCase()] = convert(currency);
+        });
 
-      setConversion(converted);
-    } else if (typeof to === 'string') {
-      setConversion(convert(to));
-    }
-  }, [convert, to]);
+        return converted;
+      } else if (typeof to === 'string') {
+        return convert(to);
+      }
 
-  return conversion;
+      return undefined;
+    },
+    [rootOptions]
+  );
 };