Types
q1.
What's the type of: "Hello"
Ans: String
q2.
What's the type (including subtypes) of:
{hello: 1}
Ans: Object, key is a string, value is an integer
q3.
What's the type of:
[1,2,3]
Ans: Array of integers
q4.
What's the type of:
[{hello: 1}, {hello: 1}]
Ans: Array of objects with strings as keys and integers as values
q5.
What's the type of:
{ cats: [{name: 'tiddles', breed: 'persian'}, {name: 'happy', breed: 'burmese'}], dogs: [{name: 'Chester', breed: 'labrador'}, {name: 'happy', breed: 'corgi'}] }
Ans: Object with strings as keys, values are arrays comprised of further objects both they keys and values of which are strings
q6.
What types does _.map accept as parameters? What does it return in each case?
Ans: Accepts arrays and a function object to be called for each element of this array. Returns a new array where each element is the return value for this function.
q7.
What types does _.filter accept as parameters? What does it return in each case?
Ans: Accepts arrays and a function object to be called for each element of this array. Returns a new array where the elements are only the results which returned TRUE for the callback function on the original array.