**Steps to replicate the issue**:
* Go to [[https://meta.wikimedia.org/wiki/Special:Block/Example|Special:Block]] on any wiki where the Codex interface is enabled.
* Open the //Add block// form if it isn't opened yet.
* Open the developer console.
**What happens?**
```lang=text
TypeError: Cannot read properties of undefined (reading 'value')
at setDurationFromGiven (ExpiryField.vue:118:6)
at watch.immediate (ExpiryField.vue:167:5)
at tq (vue.js:5:20036)
at tW (vue.js:5:20104)
at vue.js:5:54870
at k (vue.js:5:55842)
at vue.js:5:56056
at rX (vue.js:5:56165)
at vue.js:9:14814
at setup (ExpiryField.vue:165:3)
```
The relevant part is:
```lang=js
if ( mw.util.isInfinity( given ) ) {
expiryType.value = 'preset-duration';
// Set the "infinite" option that exists.
presetDuration.value = presetDurationOptions.find(
( option ) => mw.util.isInfinity( option.value )
).value; // <--
} // ...
```
Apparently, the code assumes that there would be an "infinity" option, but this is no longer true following T401823.
**What should have happened instead?**
There should have been no errors.