CODEWITHSUNDEEP
javascripttypescriptundefined
Sohrab
Sohrab

Reputation: 1478

Cannot set property XXX of undefined in TypeScript

I want to initialize an interface in TypeScript.

export interface TestGroup {
  "id": number;
  "type": TestType;
  "interval"?: number;
}


import {TestGroup} from "../../gen/api";
public functionConfig: TestGroup;
.
.
.
this.functionConfig.id = testGroup.functionTestConfig;

I get this error:

TypeError: Cannot set property 'id' of undefined

Could you please help me?

Upvotes: 4

Views: 7980

Answers (2)

Saad Abbasi
Saad Abbasi

Reputation: 853

You can fix it by initializing an empty object {}.

export interface TestGroup {
  id: number;
  type: TestType;
  interval?: number;
}


import {TestGroup} from "../../gen/api";
public functionConfig: TestGroup = {};        <=====Assign empty object
.
.
.
this.functionConfig.id = testGroup.functionTestConfig;

Upvotes: 1

Suren Srapyan
Suren Srapyan

Reputation: 68645

Your functionConfig has a type but it is actually undefined. So you need to initialize it:

public functionConfig: TestGroup = {id: 0, type: 'YourTestTypeHere'};

or your default values for it

Comment

var activateOnWeekDay: Array<boolean> = [];

Upvotes: 3

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