#Javascript array splice arguments code#

In that function, you will pass the array and the value you want to remove as arguments. Now inside the callback function indexOf() method finds the index of the value that is 'CSS' in this case. function removeElementAtIndex (arr, i) _ez_fad_position('div-gpt-ad-webmound_com-large-mobile-banner-2-0') To solve this issue, you can create your own function. Although you might get away with calling Array.prototype methods on a non-Array in many browsers today, the only place it is actually safe to do so is on arguments.If not specified, then only the existing element will be deleted, and no new element will be added. You quite often see people using the Array.prototype methods on objects that aren't Arrays the ECMAScript Third Edition standard goes out of its way to say this is OK to do for the arguments array-like, but not that you may also do it on other array-likes that may be host objects, such as NodeList or HTMLCollection. This is another of JavaScript's weird mistakes. It has it be called explicitly through the Array.prototype because arguments is not an Array, even though it looks just like one, so doesn't have the normal array methods. *: array.slice() is the normal idiom for copying an array, and array.slice(1) for taking the tail. Until browsers have implemented it, you can pick up an a fallback JS-native version from the bottom of this answer.

Partial function application is also a feature of the function.bind method, being standardised by ECMAScript Fifth Edition. It would be better to say - as the version in the answer you linked to indeed does: var args = (arguments, 1) The extra array being produced, then altered and thrown away is quite redundant. Var args = (arguments).splice(1) įirst takes a copy of arguments(*), then removes all but the first item from it (in a non-standard way), and assigns those items being removed to args.

splice(1) doesn't work in IE (it's technically missing a 2nd parameter telling it how many items to remove that IE and ECMAScript require).

#Javascript array splice arguments code#

The way the code accomplishes this is by 'tricking' the slice function (which again is not available on the arguments object) to run in the context of arguments, via : // get a reference to the slice methodĪrguments, // making 'this' point to arguments inside slice, and.ġ // pass 1 to slice as the first argumentĪ(arguments).splice(1) accomplishes the same thing, but makes an extraneous call to splice(1), which removes elements from the array returned from (arguments) starting at index 1 and continuing to the end of the array. The special arguments object (available inside the execution context of all JavaScript functions), although Array- like in that it supports indexing via the operator with numeric keys, is not actually an Array You can't. So the short answer is that the code is basically emulating: arguments.slice(1) // discard 1st argument, gimme the rest Var b = a.slice() // b is now a copy of a The actual code from that linked answer is: var args = (arguments, 1) įirst of all, the slice method is often used to make a copy of the array it's called on: var a =