isNumber-filter (#906)

src/filters/index.ts

@@ -7,6 +7,7 @@ export {isDeprecated} from './isDeprecated'
 export {isFromFile} from './isFromFile'
 export {isFontFamily} from './isFontFamily'
 export {isFontWeight} from './isFontWeight'
+export {isNumber} from './isNumber'
 export {isShadow} from './isShadow'
 export {isSource} from './isSource'
 export {isTypography} from './isTypography'

src/filters/isNumber.ts

@@ -0,0 +1,8 @@
+import type StyleDictionary from 'style-dictionary'
+
+/**
+ * @description Checks if token type is a number
+ * @param token [StyleDictionary.TransformedToken](/~https://github.com/amzn/style-dictionary/blob/main/types/TransformedToken.d.ts)
+ * @returns boolean
+ */
+export const isNumber = (token: StyleDictionary.TransformedToken): boolean => token.$type === 'number'