Class transformer: Property that is an object with properties that is another class

Jeffrey Chen 0
Viewed 47
class ClassA {
    x: number;
    y: number;
    sum(): number {
        return this.x + this.y;
    }
}

class ClassB {
    @Type(() => ClassA)
    z: {[key: string]: ClassA};
}

const b = plainToInstance(ClassB, plainObj);
const z = b.z[key];
const s = z.sum();

Error because b.z is not correctly transformed into key-value pair of ClassA, it doesn't have sum().

What is the correct way to do this?

plainObj = {z: {key1: {x: 1, y: 2}, key2: {x: 10, y: 20}}
class-transformer typescript javascript
1 Answers

Finally got it working, the docs mention usages of Map but i couldn't get it working. Turns out you also need to set "emitDecoratorMetadata": true in tsconfig.json.

you need to change your ClassB

class ClassB {
  @Type(() => ClassA)
  z: Map<string, ClassA>;
}

then it will work perfectly.

Amit Kumar0
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