Make sure we parseInt to avoid concatenating rather than adding. Also… #1
Conversation
…, add ng-bitwise attribute to indicate we should use bitwise-safe operations (3 + 1 = 4, but 3 | 1 = 3)
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Could you provide a better example of what you are trying to accomplish with the bitwise-safe operations? |
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I will accept the parseInt change btw :) |
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The problem is the digest chain. Because Angular will only digest the model once per update, it's entirely possible that something else in the chain will modify the model. If you have flag A = 1, flag B = 2, flag C = 4, and the user activates flag A. Something else in the digest chain modifies existing model and sets it to "1" BEFORE the enum-flag code runs. Then, your arithmetic will change the value to "2" rather than leaving it as "1" which is the correct operation. That's what is meant by "bitwise-safe". However, obviously this is not appropriate if the flags are not a bitfield (not powers of 2) |
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Shouldn't it always do that then? Just make it standard? Looks like I didn't thought it through well enough ;) |
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Well, the reason why I didn't think you'd want to do it as standard, is if you have a non-bitwise enum.. like 1,2,3,4,5.. rather than powers of 2.. 1,2,4,8,16,etc then the bitwise math wouldn't work. So it depends if you want this directive to be bitwise-only, or not. Actually, thinking about it, that doesn't make sense. There's no reason why anyone would want to sum values in a non-bitwise enum. So yeah, just make it standard. |
Make sure we parseInt to avoid concatenating rather than arithmetic.
Also, add ng-bitwise attribute to indicate we should use bitwise-safe operations (3 + 1 = 4, but 3 | 1 = 3). This will matter if the model is being altered elsewhere.