1.js

let addTask,
    removeTask;

addTask = (data) => {
    return {
        type: 'ADD_TASK',
        data: data
    };
};

removeTask = (data) => {
    return {
        type: 'REMOVE_TASK',
        data: data
    }
};

export {
    addTask,
    removeTask
};

2.js

let actions;

actions.addTask = (data) => {
    return {
        type: 'ADD_TASK',
        data: data
    };
};

actions.removeTask = (data) => {
    return {
        type: 'REMOVE_TASK',
        data: data
    };
};

export default actions;

3.js

/**
 * Hypothetical function that uses object key to derive type (addTask => ADD_TASK)
 * and adds "type" property to the result of the function.
 */
import giveType from './giveType';

let actions;

actions.addTask = (data) => {
    return {
        data: data
    };
};

actions.removeTask = (data) => {
    return {
        data: data
    };
};

export default giveType(actions);