deepget.js

deepget.js

function get (obj, key, fallback=undefined) {
    const keyPath = key.split('.')
    try {
        return keyPath.reduce((obj, key) => {
            if (!(key in obj)) throw new TypeError()
            return obj[key]
        }, obj)
    } catch (e) {
        return fallback
    }
}

console.log(get({a: 1}, 'a'))
console.log(get({a: 1}, 'b', 2))
console.log(get({a: {b: {c: 1}}}, 'a.b.c'))
console.log(get({a: {b: {c: 1}}}, 'a.b.c'))

const foo = {a: {b: {c: 1}}}
const b = get(foo, 'a.b')
b.c = 2
console.log(foo)