Objects implementing an interface that is declared to be iterable The difference is important, because DOM4 now defines NodeLists as iterable. Previously, some browsers returned a NodeList instead. Getter Element? namedItem(DOMString name) Getter Element? item(unsigned long index) map(element => element.innerHTML) Īs already said, getElementsB圜lassName returns a HTMLCollection, which is defined as While the alternative function querySelectorAll (which kinda makes getElementsB圜lassName obsolete) returns a collection which does have forEach natively, other methods like map or filter are missing, so this syntax is still useful. works on all array-like objects, not only arrays themselves, then good old array syntax is used to construct an array from the values. In older browsers which don't support om, you need to use something like Babel.ĮS6 also adds this syntax. Deleted elements are not visited.You can use om to convert collection to array, which is way cleaner than : om(document.getElementsB圜lassName("myclass")).forEach(
If an existing, yet-unvisited element of the array is changed by callbackFn, its value passed to the callbackFn will be the value at the time that element gets visited. Changes to already-visited indexes do not cause callbackFn to be invoked on them again. callbackFn will not visit any elements added beyond the array's initial length when the call to forEach() began. Note, however, that the length of the array is saved before the first invocation of callbackFn. It is not invoked for empty slots in sparse arrays.įorEach() does not mutate the array on which it is called, but the function provided as callbackFn can. The typical use case is to execute side effects at the end of a chain.ĬallbackFn is invoked only for array indexes which have assigned values. Unlike map(), forEach() always returns undefined and is not chainable. It calls a provided callbackFn function once for each element in an array in ascending-index order. The forEach() method is an iterative method. 
Object.prototype._lookupSetter_() Deprecated. Object.prototype._lookupGetter_() Deprecated. Object.prototype._defineSetter_() Deprecated. 
Object.prototype._defineGetter_() Deprecated.
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