microsoft / microsoft/TypeScript
Allow non-null assertion operator on destructuring
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Description
### 🔍 Search Terms
destructuring non null assertion operator
### ✅ Viability Checklist
- [x] This wouldn't be a breaking change in existing TypeScript/JavaScript code
- [x] This wouldn't change the runtime behavior of existing JavaScript code
- [x] This could be implemented without emitting different JS based on the types of the expressions
- [x] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
- [x] This isn't a request to add a new utility type: https://github.com/microsoft/TypeScript/wiki/No-New-Utility-Types
- [x] This feature would agree with the rest of our Design Goals: https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals
### ⭐ Suggestion
Allow the non-null assertion post-fix operator to be used in destructuring assignments
### 📃 Motivating Example
I was destructuring an object with a long name, but I couldn't do so because I also needed to assert it wasn't null, and this is not currently allowed
```ts
const { veryVeryVeryLongPropertyName! } = obj;
```
So I had to do this
```ts
const veryVeryVeryLongPropertyName = obj.veryVeryVeryLongPropertyName!;
```
### 💻 Use Cases
### What do you want to use this for?
To avoid having to specify the name twice
### What workarounds are you using in the meantime?
```ts
// Workaround: Short name
// Shortcoming: Not what I actually wanted to do
const temp = obj.veryVeryVeryLongPropertyName!;
// Workaround: Default `never` value
// Shortcoming: Verbose
const { veryVeryVeryLongPropertyName = undefined! } = obj;
```
Guide de contribution
Ouvrir le guide de contribution
Piste de recherche
Commencez par les exemples de déstructuration de l’issue et par la contrainte indiquée selon laquelle le JavaScript généré ne doit pas changer. Examinez la gestion par le compilateur des assertions non-null et des affectations par déstructuration, puis définissez la conception et les tests requis ; le travail est terminé lorsque la syntaxe proposée est acceptée sans modifier la sortie à l’exécution.
Rédigé par le modèle d'indexation à partir du texte de l'issue.
Évaluation
- Stack technique
- typescript
- Domaine
- compilers
- Type d'issue
- Fonctionnalité
- Difficulté
- 5/5
- Temps estimé
- Plus d'une semaine
- Activité
- À l'abandon
- Clarté
- Plutôt claire
- Accessibilité débutants
- 35/100