This is one of those it seems so simple, but I cannot come up with a good way to go about it.
I have a node, maybe nodelist = document.getElementById("mydiv"); - I need to normalize this to a node list. And not an array either: an actual, bona-fide nodeList object.
Not nodelist = [document.getElementById("mydiv")];
No libraries, please.
Reviving this because I recently remembered something about JavaScript. This depends on how the NodeList is being checked, but..
const singleNode = ((nodeList) => (node) => {
const layer = { // define our specific case
0: { value: node, enumerable: true },
length: { value: 1 },
item: {
value(i) {
return this[+i || 0];
},
enumerable: true,
},
};
return Object.create(nodeList, layer); // put our case on top of true NodeList
})(document.createDocumentFragment().childNodes); // scope a true NodeList
Now, if you do
const list = singleNode(document.body); // for example
list instanceof NodeList; // true
list.constructor === NodeList; // true
and list has properties length 1 and 0 as your node, as well as anything inherited from NodeList.
If you can't use Object.create, you could do the same except as a constructor with prototype nodelist and set this['0'] = node;, this['length'] = 1; and create with new.
ES5 version
var singleNode = (function () {
// make an empty node list to inherit from
var nodelist = document.createDocumentFragment().childNodes;
// return a function to create object formed as desired
return function (node) {
return Object.create(nodelist, {
'0': {value: node, enumerable: true},
'length': {value: 1},
'item': {
"value": function (i) {
return this[+i || 0];
},
enumerable: true
}
}); // return an object pretending to be a NodeList
};
}());
list.item, you'll have to shadow it to avoid an illegal invocation (perhaps use two-level prototyping). –
Assuasive singleNode return a self-executing function? It seems to work fine by just returning the Object.create... after creating the empty DocumentFragment? Is it just so the document fragment is created once, no matter how many times it's called? –
Provincetown Take any element already referenced in JavaScript, give it an attribute we can find using a selector, find it as a list, remove the attribute, return the list.
function toNodeList(elm){
var list;
elm.setAttribute('wrapNodeList','');
list = document.querySelectorAll('[wrapNodeList]');
elm.removeAttribute('wrapNodeList');
return list;
}
Extended from bfavaretto's answer.
function toNodeList(elm, context){
var list, df;
context = context // context provided
|| elm.parentNode; // element's parent
if(!context && elm.ownerDocument){ // is part of a document
if(elm === elm.ownerDocument.documentElement || elm.ownerDocument.constructor.name === 'DocumentFragment'){ // is <html> or in a fragment
context = elm.ownerDocument;
}
}
if(!context){ // still no context? do David Thomas' method
df = document.createDocumentFragment();
df.appendChild(elm);
list = df.childNodes;
// df.removeChild(elm); // NodeList is live, removeChild empties it
return list;
}
// selector method
elm.setAttribute('wrapNodeList','');
list = context.querySelectorAll('[wrapNodeList]');
elm.removeAttribute('wrapNodeList');
return list;
}
There is another way to do this I thought of recently
var _NodeList = (function () {
var fragment = document.createDocumentFragment();
fragment.appendChild(document.createComment('node shadows me'));
function NodeList (node) {
this[0] = node;
};
NodeList.prototype = (function (proto) {
function F() {} // Object.create shim
F.prototype = proto;
return new F();
}(fragment.childNodes));
NodeList.prototype.item = function item(i) {
return this[+i || 0];
};
return NodeList;
}());
Now
var list = new _NodeList(document.body); // note **new**
list.constructor === NodeList; // all these are true
list instanceof NodeList;
list.length === 1;
list[0] === document.body;
list.item(0) === document.body;
elm.nodeType !== 1) –
Assuasive Array.prototype.item = function(i){return this[i];};) –
Assuasive Invalid Invocation error on Chrome. 4th and 5th conditions are evaluating to false on Firefox, but true on Chrome. –
Alleen If you're targeting browsers that support document.querySelectorAll, it will always return a NodeList. So:
var nodelist = document.querySelectorAll("#mydiv");
Reviving this because I recently remembered something about JavaScript. This depends on how the NodeList is being checked, but..
const singleNode = ((nodeList) => (node) => {
const layer = { // define our specific case
0: { value: node, enumerable: true },
length: { value: 1 },
item: {
value(i) {
return this[+i || 0];
},
enumerable: true,
},
};
return Object.create(nodeList, layer); // put our case on top of true NodeList
})(document.createDocumentFragment().childNodes); // scope a true NodeList
Now, if you do
const list = singleNode(document.body); // for example
list instanceof NodeList; // true
list.constructor === NodeList; // true
and list has properties length 1 and 0 as your node, as well as anything inherited from NodeList.
If you can't use Object.create, you could do the same except as a constructor with prototype nodelist and set this['0'] = node;, this['length'] = 1; and create with new.
ES5 version
var singleNode = (function () {
// make an empty node list to inherit from
var nodelist = document.createDocumentFragment().childNodes;
// return a function to create object formed as desired
return function (node) {
return Object.create(nodelist, {
'0': {value: node, enumerable: true},
'length': {value: 1},
'item': {
"value": function (i) {
return this[+i || 0];
},
enumerable: true
}
}); // return an object pretending to be a NodeList
};
}());
list.item, you'll have to shadow it to avoid an illegal invocation (perhaps use two-level prototyping). –
Assuasive singleNode return a self-executing function? It seems to work fine by just returning the Object.create... after creating the empty DocumentFragment? Is it just so the document fragment is created once, no matter how many times it's called? –
Provincetown Yet another way to do this based on Reflect.construct: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/construct
As in other cases it requires patching NodeList.prototype.item to make calls to this function work.
NodeList.prototype.item = function item(i) {
return this[+i || 0];
};
let nl = Reflect.construct(Array, [], NodeList);
To create it with nodes pass array of nodes as second argument. This method passes checks:
list instanceof NodeList; // true
list.constructor === NodeList; // true
Array, created with it, is iterable with for..of, forEach and other standard methods and you can add elements into it with simple nl[n] = node;.
+i syntax (never seen that before) but Reflect.construct() works well. –
Quyenr :scope > :nth-child(${Array.from(div.parentNode.children).indexOf(div)+1})) Not sure about compatibility with Safari 12 and it won't work in IE11 for sure, but it returns actual NodeList. Element must have a parent, though. Could be solved by temporarily adding it into another element in case parentNode is null. –
Gigot var nodeList = document.createDocumentFragment();
nodeList.appendChild(document.getElementById("myDiv"));
nodeList instanceof NodeList returns false. –
Hough console.log(nodeList.childNodes instanceof NodeList); // returns true –
Smallish Thanks @lao
var nodeList = document.createDocumentFragment();
nodeList.appendChild(document.getElementById("myDiv"));
nodeList = nodeList.childNodes
console.log(nodeList instanceof NodeList);
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