typescript - dynamic new class object name

Question

I need to create a new class objects in loop where I can provide a dynamic name of this class, e.g. I have class "tree":

export default class ParentClass {
    // ...
}

export default class Thomas extends ParentClass {
    // ...
}

export default class Paul extends ParentClass {
    // ...
}

and loop:

const workers = ['Thomas', 'Paul'];
for (const worker of workers) {
    const h = new <worker>();
    // do something with this object
}

Is it possible to do this? Project using NodeJS with Express.js.

Does all the names in the workers-array correspond to an existing class? — John
– John, Commented Sep 9, 2019 at 11:07
@John Yes, I'm not allowing to use "name" of non-existing class. — Damian
– Damian, Commented Sep 9, 2019 at 11:11

eosterberg · Accepted Answer · 2019-09-09 11:11:32Z

3

This is possible, either you can put the class constructors right in the array:

const workers = [Thomas, Paul];
for (const workerConstructor of workers) {
  const h = new workerConstructor();
  // do something with this object
}

Or, put them in a map so you can access them using a string key:

const classMap = {
  'Thomas': Thomas,
  'Paul': Paul
}

const workers = ['Thomas', 'Paul'];
for (const workerKey of workers) {
  const h = new classMap[workerKey]();
  // do something with this object
}

answered Sep 9, 2019 at 11:11

eosterberg

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Comments

John · Accepted Answer · 2019-09-09 11:11:50Z

0

You could do something like this:

const workers = ['Thomas', 'Paul'];
for (const worker of workers) {
    let c;
    eval("c=new "+worker+"()");
    // do something with this object
}

answered Sep 9, 2019 at 11:11

John

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