Unexpected behaviour while using a Map

[robpre]

I believe I've encountered a bug/unexpected behaviour while trying to access the property of a Model. Say we have a model/map that looks like:

var test = new can.Model({
    'my.item': false
});

and we access it by

var result = test.attr('my.item');

then result is === undefined, instead of false.

I have a small change in mind which will resolve this issue, by making a change to this check https://github.com/bitovi/canjs/blob/master/map/map.js#L647 .

var value;
if( typeof attr === 'string' && !!~attr.indexOf('.') ) {
    value = this.__get(attr);
    if( value !== undefined ) {
        return value;
    }
}

I have this ready for pull request, unless of course this is expected :)

I have reproduced it in this fiddle http://jsfiddle.net/qd73h/1/.

[justinbmeyer]

This is expected behavior. You read that property like: "my.item".

Sent from my iPhone

On Jan 15, 2014, at 10:19 AM, Robert Preus-MacLaren notifications@github.com wrote:

I believe I've encountered a bug/unexpected behaviour while trying to access the property of a Model. Say we have a model/map that looks like:

var test = new can.Model({
'my.item': false
});
and we access it by

var result = test.attr('my.item');
then result is === undefined, instead of false.

I have a small change in mind which will resolve this issue, by making a change to this check https://github.com/bitovi/canjs/blob/master/map/map.js#L647 .

var value;
if( typeof attr === 'string' && !!~attr.indexOf('.') ) {
value = this.__get(attr);
if( value !== undefined ) {
return value;
}
}
I have this ready for pull request, unless of course this is expected :)

I have reproduced it in this fiddle http://jsfiddle.net/qd73h/1/.

—
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[thecountofzero]

I think this might be broken only when the value you are trying to retrieve is falsey.

http://jsfiddle.net/thecountofzero/tt7uL/

[robpre]

Precisely @thecountofzero , there appears to be a check for "." and then to return that element if it is found. But the check is only if it's truthy, this is very odd behaviour, shouldn't it be one or the other? @justinbmeyer
https://github.com/bitovi/canjs/blob/master/map/map.js#L648
https://github.com/bitovi/canjs/blob/master/map/map.js#L650

The Attr functionality currently works like this

var result, test = new can.Model({
    'my.enable': false,
    'my.item': true,
    'my.count': 0,
    'my.newCount': 1
});

result = test.attr('my.enable'); // result === undefined
result = test.attr('my.item'); // result === true
result = test.attr('my.count'); // result === undefined
result = test.attr('my.newCount'); // result === 1

That doesn't feel right to me.

[justinbmeyer]

Use the "."

Sent from my iPhone

On Jan 16, 2014, at 4:04 AM, Robert Preus-MacLaren notifications@github.com wrote:

Precisely @thecountofzero , there appears to be a check for "." and then to return that element if it is found. But the check is only if it's truthy, this is very odd behaviour, shouldn't it be one or the other? @justinbmeyer

The Attr functionality currently works like this

var result, test = new can.Model({
'my.enable': false,
'my.item': true,
'my.count': 0,
'my.newCount': 1
});

result = test.attr('my.enable'); // result === undefined
result = test.attr('my.item'); // result === true
result = test.attr('my.count'); // result === undefined
result = test.attr('my.newCount'); // result === 1
That doesn't feel right to me.

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[thecountofzero]

Using the "." works, but if the value of the attribute you are retrieving is a falsey value, it returns "undefined".
If the value of the attribute you are retrieving is not a falsey value, it returns the correct value.

http://jsfiddle.net/thecountofzero/tt7uL/

[justinbmeyer]

Getting a falsey value should probably not work without the "".

[daffl]

Really, if you can escape the . then something like test.attr('my.item'); should only work for { my: { item: value } } and never for { 'my.item': value } (which should be test.attr('my\.item');).

[thecountofzero]

Getting a falsey value fails with the ""

[daffl]

That's why I reopened. It's really inconsistent. And broken for falsy values.

[robpre]

Out of interest, isn't it true that in javascript

"\.there's a dot\." === ".there's a dot."

So at the point we do the check the backslash is irrelevant? https://github.com/bitovi/canjs/blob/master/map/map.js#L648..
Unless I'm missing something when we check the index of "."

[andykant]

Fixed with #671.