Discovered an issue with AngularJS involving ng-show and ng-if?

Upon my investigation, I have identified multiple issues with angularjs:

<div ng-show="['[]']">this should be displayed but it is not working as expected</div>
<div ng-show="[]">this should be displayed but it is not working as expected</div>
<div ng-show="[0]">this should be displayed but it is not working as expected</div>
<div ng-show="['0']">this should be displayed but it is not working as expected</div>

When these conditions are used within an if statement in javascript, they evaluate to true. However, when utilized in ng-show, ng-hide, or ng-if, they do not behave correctly.

This discrepancy raises the question: Is this a bug?

javascriptangularjs

Answer №1

None of the statements provided above are valid. Allow me to illustrate with some examples.

// The following code creates an array containing a string of '[]', which does not have any expression that evaluates to true or false:
<div ng-show="['[]']">this should be shown but it is not</div>

// This code shows an empty array with no expression for true or false evaluation. It would be more appropriate to use myArray.length > 0, which can evaluate as true or false:
<div ng-show="[]">this should be shown but it is not</div>

// Similar to the first example, this code contains an array with one element of 0, which will never evaluate to true or false:
<div ng-show="[0]">this should be shown but it is not</div>

// This code follows the same pattern as the previous examples:
<div ng-show="['0']">this should be shown but it is not</div>

The ng-show/if directive is not being used correctly. You must always provide an expression that can be evaluated as either true or false, or a function that returns true or false. Do not confuse your Angular code in the HTML with your JavaScript logic.

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