Which function is used to clone an object in Underscore.js?
A). _.extend
B). _.clone
C). _.map
D). _.filter
How do you check if a value is an array in Underscore.js?
A). _.isObject
B). _.isArray
C). _.isArguments
D). _.isString
What is the result of _.reduce([1, 2, 3], function(sum, num) { return sum + num; }, 0)?
A). 6
B). 5
C). 3
D). 2
What does _.pluck([{a: 1}, {a: 2}, {a: 3}], 'a') return?
A). [1, 2, 3]
B). [1, 2]
C). [2, 3]
D). [3, 1]
What is the result of _.map([1, 2, 3], function(num) { return num * 3; })?
A). [1, 2, 3]
B). [3, 6, 9]
C). [2, 4, 6]
D). [3, 6, 9, 12]
Which function is used to find unique elements in an array in Underscore.js?
A). _.first
B). _.last
C). _.uniq
D). _.filter
What does the _.filter function do in Underscore.js?
A). Iterates over a list of elements
B). Creates a new array with transformed values
C). Filters values in a list
D). Reduces the list to a single value
What is the output of _.last([1, 2, 3, 4, 5], 2)?
A). [1, 2]
B). [4, 5]
C). [5]
D). [3, 4, 5]
How can you invoke a function a specified number of times in Underscore.js?
A). _.times
B). _.invoke
C). _.repeat
D). _.cycle
What does _.keys({one: 1, two: 2, three: 3}) return?
A). [1, 2, 3]
B). ['one', 'two', 'three']
C). ['1', '2', '3']
D). [1, 2, 'three']