language service suggestion for Declare property '...' in constructor argument

Search Terms

• typescript declare property in constructor
• typescript language service declare property in constructor

Suggestion

When a non-existing property x is accessed on this in a class method, one of the fixes that ts language service currently suggests, is:

Declare property x

Which adds property x to the class.
It would be nice to also have Declare property x in constructor arguments.
It can use private access modifier by default.

Use Cases

While it's generally useful, it becomes especially handy when developing applications with DI frameworks like Angular that use constructor injection to wire dependencies together.

Examples

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Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript / JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. new expression-level syntax)

Start with the existing TypeScript language-service suggestion for “Declare property x” and trace its code-fix entry point and tests, if present. Add the requested alternative for declaring x in constructor arguments with private as the default modifier, then verify the suggestion in the described class-method case and its generated result.