javascript array splice not working as expected

The elements to add to the array, beginning from start.

In this case, you should specify at least one new element (see below). If deleteCount is 0 or negative, no elements are removed. However, if you wish to pass any itemN parameter, you should pass Infinity as deleteCount to delete all elements after start, because an explicit undefined gets converted to 0. If deleteCount is omitted, or if its value is greater than or equal to the number of elements after the position specified by start, then all the elements from start to the end of the array will be deleted. This is different from passing undefined, which is converted to 0.Īn integer indicating the number of elements in the array to remove from start. If start is omitted (and splice() is called with no arguments), nothing is deleted.Negative index counts back from the end of the array - if start = array.length, no element will be deleted, but the method will behave as an adding function, adding as many elements as provided.Zero-based index at which to start changing the array, converted to an integer. Object.prototype._lookupSetter_() Deprecated.Object.prototype._lookupGetter_() Deprecated.Object.prototype._defineSetter_() Deprecated.Object.prototype._defineGetter_() Deprecated.To compare numbers instead of strings, the compare function can subtract bįrom a. The default lexicographic comparator satisfies all constraints above. A comparator that always returns 0 will cause the array to not be changed at all, but is reliable nonetheless. For example, if a comparator only returns 1 and 0, or only returns 0 and -1, it will not be able to sort reliably because anti-symmetry is broken. Transitive: If compareFn(a, b) and compareFn(b, c) are both positive, zero, or negative, then compareFn(a, c) has the same positivity as the previous two.Ī comparator conforming to the constraints above will always be able to return all of 1, 0, and -1, or consistently return 0.Anti-symmetric: compareFn(a, b) and compareFn(b, a) must both be 0 or have opposite signs.Stable: The comparator returns the same result with the same pair of input.To solve the error, convert the value to an array before calling the method or make sure to only call the splice() method on valid arrays. (This is important because there's no guarantee when and how the comparator will be called, so any particular call should not produce visible effects to the outside.) The 'TypeError: splice is not a function' error occurs when the splice() method is called on a value that is not an array. Pure: The comparator does not mutate the objects being compared or any external state.When three dots () occurs in a function call or alike, it's called a 'spread operator' and expands an array into a list. More formally, the comparator is expected to have the following properties, in order to ensure proper sort behavior: There's an easy way to distinguish between them: When three dots () is at the end of function parameters, it's 'rest parameters' and gathers the rest of the list of arguments into an array. The rest of the parameters ('Lemon', 'Kiwi') define the new elements to be added. The second parameter (0) defines how many elements should be removed. Object.prototype._defineSetter_() Deprecated The first parameter (2) defines the position where new elements should be added (spliced in).

Javascript array splice not working as expected