end will take the element before the element you specified as the end.start will take the element you specified as the start.It means that the very first element in the array has the index 0 and the second one has the index 1.
There are a few rules you need to remember about the start and end parameters.Īrrays are indexed: every element has an index which can be used to refer to it. Using a few practical examples, let's take a closer look at the slice method in JavaScript. The slicing conditions can be set as start and end parameters.It leaves the original array untouched.The slice method creates a copy of an array or a part of it based on specified conditions.With just this one array, you can create a web page that can change its content ad hoc showing all names or only some of them, for instance, when the user applies a filter. In this example, fruits is an array of simple items which are strings.
The definition of '' in that specification.Const fruits = Handle negative value for "end" var upTo = ( typeof end = ' number') ? Math.min(end, len) : len * Shim for "fixing" IE's lack of support (IE = 0) ? start : Math.max( 0, len + start) Var list1 = list( 1, 2, 3) // Streamlining cross-browser behaviorĪlthough host objects (such as DOM objects) are not required by spec to follow the Mozilla behavior when converted by and IE = 9, now do.) Examples Return a portion of an existing arrayĬopy Code var unboundSlice = If a new element is added to either array, the other array is not affected. Changes to the string, number or boolean in one array does not affect the other array. For strings, numbers and booleans (not String, Number and Boolean objects), slice copies the values into the new array.If a referenced object changes, the changes are visible to both the new and original arrays. Both the original and new array refer to the same object. For object references (and not the actual object), slice copies object references into the new array.Elements of the original array are copied into the returned array as follows: It returns a shallow copy of elements from the original array. Return valueĪ new array containing the extracted elements. If end is omitted, slice extracts through the end of the sequence ( arr.length). slice(2,-1) extracts the third element through the second-to-last element in the sequence. As a negative index, end indicates an offset from the end of the sequence. slice(1,4) extracts the second element through the fourth element (elements indexed 1, 2, and 3).
slice extracts up to but not including end. end Zero-based index at which to end extraction. If begin is undefined, slice begins from index 0. slice(-2) extracts the last two elements in the sequence. As a negative index, begin indicates an offset from the end of the sequence. slice(]) Parameters begin Zero-based index at which to begin extraction.
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