Changing value from "" to 0 doesn't update DOM

[tivac]

http://jsbin.com/susifidowo/1/edit?js,output

We ran into an issue with text fields that are numeric, but able to blanked out (such as a user clearing the field before entering a new value). If the value is an empty string, and we then try to set the value to 0 and re-render the diff is empty and the result doesn't change.

Repro:

1. Load JsBin
2. Note empty input
3. Click "zero" button, note input contains 0.
4. Click "value" button, note input contains 125.
5. Click "empty" button, note input is empty.
6. Click "zero" button, note input remains empty.
7. Click "value" button, note input contains 125

Expected:
When input is empty and the value is change to 0, the input value would change in the next render.

Note: This isn't a problem going from 0 to an empty string, in that case it properly updates the input value.

Repro Code

var model = {
  val : ""
};

//initialize
m.module(document.body, {
  controller : function() {
    this.clickEmpty = function(e) {
      e.preventDefault();

      model.val = "";
    };

    this.clickZero = function(e) {
      e.preventDefault();

      model.val = 0;
    };

    this.clickValue = function(e) {
      e.preventDefault();

      model.val = 125;
    };
  },

  view : function(ctrl) {
    return [ 
      m("input", { value : model.val }),
      m("button", { onclick : ctrl.clickEmpty }, "empty"),
      m("button", { onclick : ctrl.clickZero }, "zero"),
      m("button", { onclick : ctrl.clickValue }, "value")
    ];
  }
});

[Naddiseo]

Perhaps model.val should always be a string. If I use model.val = "0" it works again.

[lhorie]

related to #367

[tivac]

@lhorie that was my suspicion as well, but figured I'd report any ways. I haven't tracked down where exactly this is running into trouble but I'm hoping I'll be able to look soon.

[lhorie]

Fixed in origin/next

[tivac]

@lhorie awesome, thanks!