TDD和重新创建下划线功能

Question

So I'm getting an error on the last test: "Assertion failed:", should produce a brand new array instead of modifying the input array.

I thought I was creating a new array but I'm unsure of what the test is wanting. Is it saying I need to create a new empty array and then push the correct values into the new array? I don't see whats wrong with the way I'm doing it now, but it seems to want me to do something else.

_.uniq = function(array) {
    var newArray = array;
    _.each(newArray, function(val,i){
        for(var j = 0; j < newArray.length; j++)
            if(val === newArray[j] && i !== j){
        array.splice(j,1);
            }
    })
    return newArray;
}

Test:

describe('uniq', function() {
  it('should return all unique values contained in an unsorted array', function() {
    var numbers = [1, 2, 1, 3, 1, 4]

    expect_equal(_.uniq(numbers), [1, 2, 3, 4])
  })

  it('should handle iterators that work with a sorted array', function() {
    var iterator = function(value) { return value + 1 }
    var numbers = [1, 2, 2, 3, 4, 4]

    expect_equal(_.uniq(numbers, true, iterator), [1, 2, 3, 4])
  })

  it('should produce a brand new array instead of modifying the input array', function() {
    var numbers = [1, 2, 1, 3, 1, 4]
    var uniqueNumbers = _.uniq(numbers)

    console.assert(uniqueNumbers !== numbers)
  })
})

Answer 1

ended up solving it with this:

_.uniq = function(array) {
    var newArray = [];
    _.each(array, function(val){
        newArray.push(val); 
    })
    _.each(newArray, function(val,i){

        for(var j = 0; j < newArray.length; j++)
            if(val === newArray[j] && i !== j){
        newArray.splice(j,1);
            }
    })
    return newArray;
}