[1.x]Empty string should not be casted to 0 (fix vuejs#3577, vuejs#3541) (vuejs#4118)

defcc · yyx990803 · commit 12ecce5b4dd9 · 2016-11-04T11:46:43.000-04:00
* 	empty string should not be casted to 0. Backport it from vue2

* trim whitespace

* fix coding style

* fix coding style
diff --git a/src/util/lang.js b/src/util/lang.js
@@ -126,14 +126,13 @@ export function _toString (value) {
  */
 
 export function toNumber (value) {
-  if (typeof value !== 'string') {
+  if (typeof value !== 'string' || value.trim() === '') {
     return value
-  } else {
-    var parsed = Number(value)
-    return isNaN(parsed)
-      ? value
-      : parsed
   }
+  var parsed = Number(value)
+  return isNaN(parsed)
+    ? value
+    : parsed
 }
 
 /**
