TS declaration declares currency global (#297)

* TS declaration declares currency global

ISSUE: The currency export is also declared globally as a namespace const and constructor.

When importing currency.js once in a module, TypeScript loads this declaration file and declares `currency` global and assumes it's available in all modules. This is not true and will give runtime errors. Exporting`currency` inside the module declaration ensures it's is imported in every module that is using it because TS will give compile errors.

* formatting

Co-authored-by: Jason <jason@scurker.com>

src/currency.d.ts

@@ -1,42 +1,42 @@
-declare namespace currency {
-  type Any = number | string | currency;
-  type Format = (currency?: currency, opts?: Options) => string;
-  interface Constructor {
-    (value: currency.Any, opts?: currency.Options): currency,
-    new (value: currency.Any, opts?: currency.Options): currency
-  }
-  interface Options {
-    symbol?: string,
-    separator?: string,
-    decimal?: string,
-    errorOnInvalid?: boolean,
-    precision?: number,
-    increment?: number,
-    useVedic?: boolean,
-    pattern?: string,
-    negativePattern?: string,
-    format?: currency.Format,
-    fromCents?: boolean
+declare module 'currency.js' {
+  namespace currency {
+    type Any = number | string | currency;
+    type Format = (currency?: currency, opts?: Options) => string;
+    interface Constructor {
+      (value: currency.Any, opts?: currency.Options): currency,
+      new(value: currency.Any, opts?: currency.Options): currency
+    }
+    interface Options {
+      symbol?: string,
+      separator?: string,
+      decimal?: string,
+      errorOnInvalid?: boolean,
+      precision?: number,
+      increment?: number,
+      useVedic?: boolean,
+      pattern?: string,
+      negativePattern?: string,
+      format?: currency.Format,
+      fromCents?: boolean
+    }
   }
-}
 
-declare interface currency {
-  add(number: currency.Any): currency;
-  subtract(number: currency.Any): currency;
-  multiply(number: currency.Any): currency;
-  divide(number: currency.Any): currency;
-  distribute(count: number): Array<currency>;
-  dollars(): number;
-  cents(): number;
-  format(opts?: currency.Options | currency.Format): string;
-  toString(): string;
-  toJSON(): number;
-  readonly intValue: number;
-  readonly value: number;
-}
+  interface currency {
+    add(number: currency.Any): currency;
+    subtract(number: currency.Any): currency;
+    multiply(number: currency.Any): currency;
+    divide(number: currency.Any): currency;
+    distribute(count: number): Array<currency>;
+    dollars(): number;
+    cents(): number;
+    format(opts?: currency.Options | currency.Format): string;
+    toString(): string;
+    toJSON(): number;
+    readonly intValue: number;
+    readonly value: number;
+  }
 
-declare const currency : currency.Constructor;
+  const currency: currency.Constructor;
 
-declare module 'currency.js' {
   export = currency;
 }