tuts-spread-02.js

// our base for making copies
const baseUnit = {
    movement: 10,
    hp: 100,
    attributes: {
        str: 12,
        dex: 8,
        con: 18,
    },
}

console.log(baseUnit)
// => { movement: 10, hp: 100, attributes: { str: 12, dex: 8, con: 18 } }

// a simple copy with nothing new but a name
const createUnitCopy = (base, name) => ({
    ...base,
    name,
})

const unitCopy = createUnitCopy(baseUnit, 'Hansel')

console.log(baseUnit)
// => { movement: 10, hp: 100, attributes: { str: 12, dex: 8, con: 18 } }
console.log(unitCopy)
// => { movement: 10, hp: 100, attributes: { str: 12, dex: 8, con: 18 }, name: 'Hansel' }

// a stronger version of our regular copies
const createEnhancedUnitCopy = (base, name, newstr) => {
    const { attributes, ...rest } = base
    attributes.str = newstr

    return {
        ...rest,
        attributes,
        name,
    }
}

const betterUnit = createEnhancedUnitCopy(baseUnit, 'Gretel', 23)

console.log(baseUnit)
// => { movement: 10, hp: 100, attributes: { str: 23, dex: 8, con: 18 } }
console.log(unitCopy)
// => { movement: 10, hp: 100, attributes: { str: 23, dex: 8, con: 18 }, name: 'Hansel' }
console.log(betterUnit)
// => { movement: 10, hp: 100, attributes: { str: 23, dex: 8, con: 18 }, name: 'Gretel' }