Implement lodash get function - kdaisho/Blog GitHub Wiki

We're going to implement lodash get function. https://lodash.com/docs#get

The function should take path argument as string or array. (_.get(object, path, [defaultValue]))

It returns default value when an invalid path is given, otherwise it returns the value from the given object.

function myGet(obj, path, defaultValue) {
  const pathArray = typeof path === 'string' ? path.split('.') : path
  
  while (pathArray.length) {
    obj = obj[pathArray[0]]
    if (!obj) {
      return defaultValue
    }
    pathArray.shift()    
  }
  
  return obj
}

const myObj = {
  a: {
    b: {
      c: 'hello'
    }
  }
}

// Usage (with string path)
myGet(myObj, 'a.b.c', 'nope') // 'hello'
myGet(myObj, 'a.b', 'nope') // { c: 'hello' }
myGet(myObj, 'a.b.x', 'nope') // 'nope'

// Usage (with array path)
myGet(myObj, ['a','b','c'], 'nope') // 'hello'