How to use spread operator in javascript?-CodePudding

Hi i have code like below,

async createItem(params: ItemParams, id?: any): Promise<Item> {
    const { ...fields } = params; //remove spread operator here
    try {
        const { data: any} = await this.post(`/${ITEM}/`, keysToSnakeCase(fields)); //how can i rewrite this
        //some logic
    }
}

now i want to remove spread operator in line

const { ...fields } = params;

how can i do this. I have tried,

const {fields } = params; // says fields doesnt exist on params error.

could someone help me with this. thanks

CodePudding user response：

The ...fields part could be redundant in this scenario. The spread operator takes all the remaining key value pairs in your object and assigns them to a new object.

In your case fields is by value identical to params.

(Note: fields and params are equal by value, not by reference.)

You can simply rewrite your code like this:

async createItem(params: ItemParams, id?: any): Promise<Item> {
    try {
        const { data: any} = await this.post(`/${ITEM}/`, keysToSnakeCase(params));
        //some logic
    }
}

if the keysToSnakeCase function modifies its properties you'll notice that your original params object changes.

If this is the case, you can add the spread operator back over there to create a shallow clone of the params object so it is not updated.

async createItem(params: ItemParams, id?: any): Promise<Item> {
    try {
        const { data: any} = await this.post(`/${ITEM}/`, keysToSnakeCase(...params));
        //some logic
    }
}

For more info on the spread syntax, please refer to: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax