Typescript is throwing an error message stating that it is unable to assign a value to the property 'version' because it is undefined

I encountered an error that I'm having trouble fixing. Can someone assist me with it?

Uncaught TypeError: Cannot set property 'version' of undefined at API.version (:5:30) at :11:8

class API {

    private message: {
        version: string,
        success: boolean
    };
    public version() {
        this.message.version = "1.0";
        console.log(this.message);
    }
}

let apiObj = new API();
apiObj.version();

Answer №1

It seems like you forgot to initialize the message property in your class, which is why it's returning as undefined when you try to access it. This is causing an error when you attempt to set a value for this.message.version = "1.0";.

An easy fix for this issue would be to provide a default value for the property:

class API {

    private message: {
        version: string,
        success: boolean
    } = {
        version: "",
        success: false
    };
}

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