How can I add a new key value pair to an existing object in Angular?

Question

How can I add a new key value pair to an existing object in Angular?

I'm looking to add a new key value pair to an existing object without declaring it inside the initial object declaration. I attempted the code below, but encountered the following error:

Property 'specialty' does not exist on type

saveFormData(value: any) {

    const saveData = {
          userPartyRoleId : Number(this.userPartyRoleId),
          notes : this.notes,
        };
    
    saveData.speciality = this.spec;
}

angular typescript object

Answer 1

Answer №1

This specific feature is unique to TypeScript. Upon initializing the saveData variable with a value, TypeScript automatically deduces that it should only have two properties: userPartyRoleId, notes, and nothing else.

If you encounter this issue, there are several potential solutions available.

Solution 1

The simplest resolution involves including speciality during the initialization of saveData. This action will ensure that the correct type is assigned to saveData.

const saveData = {
    userPartyRoleId: Number(this.userPartyRoleId),
    notes: this.notes,
    speciality: this.spec
};

Solution 2

Alternatively, consider utilizing the spread operator as suggested in the comments. By doing so, you can create a new object with the appropriate type and assign it to a separate variable.

const saveData = {
    userPartyRoleId: Number(this.userPartyRoleId),
    notes: this.notes
};

const processedData = {
    ...saveData,
    speciality: this.spec
};

Solution 3

This approach ensures that your code compiles without errors and runs smoothly. By utilizing the any type, you can instruct TypeScript to skip type-checking for saveData.

const saveData: any = {
    userPartyRoleId: Number(this.userPartyRoleId),
    notes: this.notes
};

saveData.speciality = this.spec;

While this solution resolves the immediate issue, it sacrifices TypeScript's strict-typing functionality, which serves as its primary purpose.

Answer 2

This specific feature is unique to TypeScript. Upon initializing the saveData variable with a value, TypeScript automatically deduces that it should only have two properties: userPartyRoleId, notes, and nothing else.

If you encounter this issue, there are several potential solutions available.

Solution 1

The simplest resolution involves including speciality during the initialization of saveData. This action will ensure that the correct type is assigned to saveData.

const saveData = {
    userPartyRoleId: Number(this.userPartyRoleId),
    notes: this.notes,
    speciality: this.spec
};

Solution 2

Alternatively, consider utilizing the spread operator as suggested in the comments. By doing so, you can create a new object with the appropriate type and assign it to a separate variable.

const saveData = {
    userPartyRoleId: Number(this.userPartyRoleId),
    notes: this.notes
};

const processedData = {
    ...saveData,
    speciality: this.spec
};

Solution 3

This approach ensures that your code compiles without errors and runs smoothly. By utilizing the any type, you can instruct TypeScript to skip type-checking for saveData.

const saveData: any = {
    userPartyRoleId: Number(this.userPartyRoleId),
    notes: this.notes
};

saveData.speciality = this.spec;

While this solution resolves the immediate issue, it sacrifices TypeScript's strict-typing functionality, which serves as its primary purpose.

How can I add a new key value pair to an existing object in Angular?

Answer №1

Solution 1

Solution 2

Solution 3

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