message: [bugfix] Stepper: value can not be zero
diff: @@ -49,7 +49,7 @@ export default create({
  },
  data() {
  - const value = this.range(this.value || this.defaultValue);
  + const value = this.range(this.isDef(this.value) ? this.value : this.defaultValue);
  if (value !== +this.value) {
  this.$emit('input', value);
  }
  