#51 Added value preprocessor

src/directive.js

@@ -7,6 +7,7 @@ function getOpts (mask) {
   if (mask.mask) {
     opts.mask = Array.isArray(mask.mask) ? JSON.stringify(mask.mask) : mask.mask
     opts.tokens = mask.tokens ? { ...mask.tokens } : {}
+    opts.preprocessor = mask.preprocessor;
   } else {
     opts.mask = Array.isArray(mask) ? JSON.stringify(mask) : mask
   }
@@ -31,7 +32,7 @@ const directive = () => {
     if (state.has(el) && !needUpdate(mask)) {
       return
     }
-
+    
     state.set(el, new Maska(el, getOpts(mask.value)))
   }
 }

src/maska.js

@@ -6,6 +6,10 @@ export default class Maska {
   constructor (el, opts = {}) {
     if (!el) throw new Error('Maska: no element for mask')
 
+    if (opts.preprocessor != null && typeof opts.preprocessor != 'function') {
+      throw new Error('Maska: preprocessor must be a function')
+    }
+
     if (opts.tokens) {
       for (const i in opts.tokens) {
         opts.tokens[i] = { ...opts.tokens[i] }
@@ -15,9 +19,11 @@ export default class Maska {
       }
     }
 
+
     this._opts = {
       mask: opts.mask,
-      tokens: { ...tokens, ...opts.tokens }
+      tokens: { ...tokens, ...opts.tokens },
+      preprocessor: opts.preprocessor
     }
     this._el = isString(el) ? document.querySelectorAll(el) : !el.length ? [el] : el
     this.inputEvent = (e) => this.updateValue(e.target, e)
@@ -65,7 +71,13 @@ export default class Maska {
     const digit = oldValue[position - 1]
 
     el.dataset.maskRawValue = mask(el.value, el.dataset.mask, this._opts.tokens, false)
-    el.value = mask(el.value, el.dataset.mask, this._opts.tokens)
+    let elValue = el.value;
+    
+    if (this._opts.preprocessor) {
+      elValue = this._opts.preprocessor(elValue);
+    }
+
+    el.value = mask(elValue, el.dataset.mask, this._opts.tokens)
 
     if (evt && evt.inputType === 'insertText' && position === oldValue.length) {
       position = el.value.length