how to call usemutation function from another function code example

Example 1: usemutation apollo

import { gql, useMutation } from '@apollo/client';

const ADD_TODO = gql`
  mutation AddTodo($type: String!) {
    addTodo(type: $type) {
      id
      type
    }
  }
`;


function AddTodo() {
  let input;
  const [addTodo, { data }] = useMutation(ADD_TODO);

  return (
    <div>
      <form
        onSubmit={e => {
          e.preventDefault();
          addTodo({ variables: { type: input.value } });
          input.value = '';
        }}
      >
        <input
          ref={node => {
            input = node;
          }}
        />
        <button type="submit">Add Todo</button>
      </form>
    </div>
  );
}

Example 2: apollo client mutation without component

// react-apollo includes two HOCs called graphql() and withApollo() that can be used to accomplish this.
// This example takes the withApollo() HOC approach

import React, { Component } from "react";
import { DO_MUTATION } from "./mutations";
import { withApollo } from "react-apollo";

import SomeLibrary from "SomeLibrary";

export class MyComponent extends Component {
    render() {
        return (
            <Button
                onPress={() => {
                    SomeLibrary.addListener(this.listenerHandler);
                }}
            />
        );
    }

    listenerHandler = () => {
        this.props.client.mutate({
            mutation: DO_MUTATION,
            variables: {
                some_var: "some_val",
            },
        });
    };
}
export default withApollo(MyComponent);