What is the solution to setting true and false equal to true in an AngularJS expression?

Question

What is the solution to setting true and false equal to true in an AngularJS expression?

How can I determine if an input field has been touched and is empty, without using the built-in functions in Angular?

<form-input is-invalid-on="isTouched && !gs.data.name || gs.data.name.length > 50"></form-input>

If

isTouched && !gs.data.name

evaluates to true && false, then that part of the expression becomes false.

So, my question is, how do I ensure that the entire expression evaluates to true only when the input field has been touched and is either empty or has a length greater than 50?

javascript angularjs boolean-logic

Answer 1

Answer №1

It seems that this is being utilized as an attribute directive.

is-invalid-on="(isTouched && gs.data.name.length) || gs.data.name.length > 50"

The rationale behind this? My presumption is that your gs.data.name is a string. In JavaScript, even an empty string is considered truthy, so it must be assessed for its length.

Answer 2

It seems that this is being utilized as an attribute directive.

is-invalid-on="(isTouched && gs.data.name.length) || gs.data.name.length > 50"

The rationale behind this? My presumption is that your gs.data.name is a string. In JavaScript, even an empty string is considered truthy, so it must be assessed for its length.

Answer 3

Answer №2

<input-validation show-error="(isTouched && !formData.username) || (formData.username.length > 50)"</input-validation>

Answer 4

<input-validation show-error="(isTouched && !formData.username) || (formData.username.length > 50)"</input-validation>

Answer 5

Answer №3

Consider implementing () and verifying gs.data along with

isTouched && (!gs.data || !gs.data.name || gs.data.name.length  || gs.data.name.length > 50)

<input-validation is-incomplete-if="isTouched && (!gs.data || !gs.data.name || gs.data.name.length  || gs.data.name.length > 50)"></input-validation>

Answer 6

Consider implementing () and verifying gs.data along with

isTouched && (!gs.data || !gs.data.name || gs.data.name.length  || gs.data.name.length > 50)

<input-validation is-incomplete-if="isTouched && (!gs.data || !gs.data.name || gs.data.name.length  || gs.data.name.length > 50)"></input-validation>

Answer 7

Answer №4

It seems that Angular expressions do not function exactly the same as JavaScript. You may want to try the following code snippet:

<form-input is-invalid-on="isTouched && gs.data.name.length==0 || gs.data.name.length > 50"></form-input>

Make sure you have properly initialized gs.data.name to an empty string.

Also, don't forget to include the closing angle bracket (>) in your tag.

Answer 8

It seems that Angular expressions do not function exactly the same as JavaScript. You may want to try the following code snippet:

<form-input is-invalid-on="isTouched && gs.data.name.length==0 || gs.data.name.length > 50"></form-input>

Make sure you have properly initialized gs.data.name to an empty string.

Also, don't forget to include the closing angle bracket (>) in your tag.

Answer 9

Answer №5

After much investigation, I finally discovered the root cause of its unusual behavior. Since this particular question had multiple answers, I decided against deleting it and opted to clarify what occurred instead.

The issue was traced back to the fact that isTouched consistently remained as undefined due to my erroneous placement of it outside the directive. This resulted in the expression undefined && false, rendering isInvalidOn always as false.

To resolve this, I modified the implementation by utilizing isTouched within the actual form-input template with

ng-class={invalid: isInvalidOn && isTouched}

, achieving the intended functionality.

Answer 10

After much investigation, I finally discovered the root cause of its unusual behavior. Since this particular question had multiple answers, I decided against deleting it and opted to clarify what occurred instead.

The issue was traced back to the fact that isTouched consistently remained as undefined due to my erroneous placement of it outside the directive. This resulted in the expression undefined && false, rendering isInvalidOn always as false.

To resolve this, I modified the implementation by utilizing isTouched within the actual form-input template with

ng-class={invalid: isInvalidOn && isTouched}

, achieving the intended functionality.

What is the solution to setting true and false equal to true in an AngularJS expression?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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