feat: added new parseQueryString method.

src/__tests__/static.ts

@@ -0,0 +1,34 @@
+/* tslint:disable:no-expression-statement no-object-mutation */
+
+import { factoryParameters } from '../lib/store'
+import { pm } from '../lib/utils'
+import { serializers } from '../lib/serializers'
+
+describe('static parseQueryString', () => {
+  const initialValues = { someParameter: 'test' }
+  const { parseQueryString } = factoryParameters(
+    {
+      someParameter: pm('wow', serializers.string),
+    },
+    initialValues
+  )
+
+  it('should parse a query string', () => {
+    const result = parseQueryString('?wow=nice')
+    expect(result).toEqual({ someParameter: 'nice' })
+  })
+
+  it('should return defaults if empty', () => {
+    const result = parseQueryString('')
+    expect(result).toEqual(initialValues)
+  })
+  it('should return defaults if different string', () => {
+    const result = parseQueryString('?somethingElse=cool')
+    expect(result).toEqual(initialValues)
+  })
+  it('should allow to override defaults', () => {
+    const newDefaults = { someParameter: 'otherDefault' }
+    const result = parseQueryString('', newDefaults)
+    expect(result).toEqual(newDefaults)
+  })
+})

src/lib/store.ts

@@ -1,7 +1,7 @@
 /* tslint:disable:no-expression-statement readonly-array no-shadowed-variable */
 import { Draft, enablePatches, produce } from 'immer'
 import memoizeOne from 'memoize-one'
-import { stringify } from 'query-string'
+import { stringify, parse } from 'query-string'
 import {
   createContext,
   useCallback,
@@ -294,5 +294,24 @@ export const factoryParameters = <T extends object>(
     )
   }
 
-  return { useQuery, createQueryString }
+  const parseQueryString = (
+    query: string,
+    initialValues?: Partial<T> | null
+  ): Partial<T> => {
+    const thisInitialValues =
+      typeof initialValues === 'undefined'
+        ? memCreateInitialValues(defaultInitialValues)
+        : initialValues
+    return produce({}, (draft: Draft<T>) => {
+      applyFlatConfigToState(
+        flatConfig,
+        parse(query),
+        ns,
+        draft as T,
+        thisInitialValues as T
+      )
+    })
+  }
+
+  return { useQuery, createQueryString, parseQueryString }
 }