null/undefined are not falsy when not in the root context

[dasilvacontin]

 var Mustache = require('mustache');

 var view = {
    values: ['foo', 'bar', null],
 };

 console.log( Mustache.render("{{#values}}is {{#.}}{{.}}{{/.}}{{^.}}nothing{{/.}}\n{{/values}}", view) );

Renders:

➜  test  node test.js
is foo
is bar
is [object Object]

When it should actually render:

➜  test  node test.js
is foo
is bar
is nothing

[dasilvacontin]

Also, when rending null, it should render something more useful than [object Object] like [null].

[dasilvacontin]

Actually, null has always been intended to be falsy as shown by test/files/falsy.txt, but somehow the test was passing.

[dasilvacontin]

From the lookup function:

Context.prototype.lookup = function (name) {
  var cache = this.cache;

  var value;
  if (name in cache) {
    value = cache[name];
  } else {
    var context = this, names, index;

    while (context) {
      if (name.indexOf('.') > 0) {
        value = context.view;
        names = name.split('.');
        index = 0;

        while (value != null && index < names.length)
          value = value[names[index++]];
      } else if (typeof context.view == 'object') {
        value = context.view[name];
      }

      if (value != null)
        break;

      context = context.parent;
    }

    cache[name] = value;
  }

  if (isFunction(value))
    value = value.call(this.view);

  return value;
};

If you analyse, when a value such as value != null is in a context with no parent, it was getting returned by the lookup function anyways. I'm going to add more tests for falsey values in which their context does have a parent.

[dasilvacontin]

Actually n2, undefined has always been intended to be falsy as shown by test/files/falsy.txt.

It's great to see this, because it's like a past 👍 to stop context lookup when there is actually a key (even if the value is undefined or null) as issued at #397 and suggested at #407. (/cc @janl)

[dasilvacontin]

So the problem is not that null is not considered as falsy. In fact, it's considered as falsy AS LONG as you use it on the ROOT context.

The problem is on the lookup function, so I will fix this on PR #407.

[dasilvacontin]

This gets fixed by PR #407.

[phillipj]

Fixed in a020430