Destructured parameter properties in constructor

Question

Typescript allows parameter properties

class ParameterProperty {
  constructor(private member: number) {}
}

The above creates a class with

Answer 1

What about:

class Destructed {
    private prefix: string;
    private suffix: string;

    constructor(opts: DestructedOptions) {
        Object.assign(this, opts);
    }
}

Also, there's an open issue on this: Combining destructuring with parameter properties

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Edit

If you want to avoid re-writing the properties in the class then you'll need to make the members public, when that's the case then the solution is as shown in the issue I linked to:

class Destructed {
    constructor(opts: DestructedOptions) {
        Object.assign(this, opts);
    }
}

interface Destructed extends DestructedOptions { }

let destructed = new Destructed({ prefix: "prefix", suffix: "suffix" });
console.log(destructed.prefix);
console.log(destructed.suffix);
console.log(destructed.DoesntExist); // error

(code in playground)

Answer 2

In ECMAScript, destructuring assignment results in variables in variables (not properties than properties) receiving the component values.

There has been a TypeScript feature request/suggestion for combining destructuring with parameter properties open since October of 2015. That would probably be the most effective place to track the status of whatyou want.

Answer 3

There's no obvious, direct way to do what you want. Consider holding options in your class instead of individual properties, as in

interface DestructedOptions {
  prefix: string;
  suffix: string;
}

class Destructed {
  constructor(public options: DestructedOptions) {}
}

<!-- in template -->
Prefix is {{options.prefix}}!!