Develop Reference

return object if list<object> value is exists (Javascript, jquery grep/map)

I'm using grep and map functions to get the object if the value is exists in the list, but it does not work well.
I have a list customList and the customObject has the int id property and List value properties.
customobject[0].id
customObject[0].value[]
What I want is check if in the List the value 5 exists.
The function what I'm using is:
var gettedcustomObject = $.grep(customList, function (e) {
var result = e.Value.map(function (a) { return a === 5;});
return result;
});
What am I doing wrong and what is the correct implementation?
Note: 2x foreach could be a solution, but customList has more than 1000 objects with 10000 values. I think that slow down the proces.

This should do it.
var gettedcustomObject = customList.filter(function(v){
var ln = v.Value.length;
for(var i = 0; i < ln; i++){
if(v.Value[i] == 5){
return true;
}
}
return false;
// Or simply:
// return v.Value.indexOf(5) != -1;
});
This will work if v.Value is an array.

You should look at some: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some#Polyfill
Way faster than the other methods like filter, map or sort as it was designed for this.
//List to work against
var arr = [];
//Populate
while (arr.length < 9999999) {
arr.push(Math.random() * 999999)
}
//Set element to find
arr[10] = "test";
//Begin timing
var d = new Date().getTime();
//Run filter
console.log(arr.filter(function(a){return a === "test"}).length > 0);
//How long did it take
console.log("`filter` took:",new Date().getTime() - d,"ms")
//Begin timing
d = new Date().getTime();
//Run filter
console.log(arr.some(function(a){return a === "test"}));
//How long did it take
console.log("`some` took:",new Date().getTime() - d,"ms")
<script>
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some#Polyfill
// Production steps of ECMA-262, Edition 5, 15.4.4.17
// Reference: http://es5.github.io/#x15.4.4.17
if (!Array.prototype.some) {
Array.prototype.some = function(fun/*, thisArg*/) {
'use strict';
if (this == null) {
throw new TypeError('Array.prototype.some called on null or undefined');
}
if (typeof fun !== 'function') {
throw new TypeError();
}
var t = Object(this);
var len = t.length >>> 0;
var thisArg = arguments.length >= 2 ? arguments[1] : void 0;
for (var i = 0; i < len; i++) {
if (i in t && fun.call(thisArg, t[i], i, t)) {
return true;
}
}
return false;
};
}
</script>

If your goal is to find the first object in the list that contains 5 in the Value property, then you're looking for Array#find and Array#indexOf:
var gettedcustomObject = customList.find(function(entry) {
return entry.Value.indexOf(5) != -1;
});
Note that Array#find was added relatively recently and so you may need a polyfill for it (which is trivial). MDN has one.
Or you could use Array#includes instead of indexOf, which will be in ES2017 and is also polyfillable:
var gettedcustomObject = customList.find(function(entry) {
return entry.Value.includes(5);
});
Live Example (using indexOf):
var customList = [
{
note: "I'm not a match",
Value: [2, 3, 4]
},
{
note: "I'm not a match either",
Value: [78, 4, 27]
},
{
note: "I'm a match",
Value: [889, 5, 27]
},
{
note: "I'm also a match, but you won't find me",
Value: [4, 6, 5]
}
];
var gettedcustomObject = customList.find(function(entry) {
return entry.Value.indexOf(5) != -1;
});
console.log(gettedcustomObject);
If your logic matching the item inside Value were more complicated, you'd use Array#some and a callback function rathe than indexOf. But when looking to see if an array for an entry in an array based on ===, indexOf or the new Array#includes are the way to go.

one approach using Array.some() and Array.indexOf(). some loop break once the element is found
var gettedcustomObject;
customobject.some(function(obj){
if(obj.value.indexOf(5) >-1){
gettedcustomObject = obj;
return true;
}
});

Remove elements from array by type of element

I have an array and I want to remove all the string elements from it.
This is what I have so far. The result is not what I want since it returns only "bicycle"
Also, I am doing this in Test Complete so I need to have a main function that logs the result.
function ex06(){
var mailBox = "mailbox";
var twenty = 20;
var isItRaining = true;
var goat = "";
var stringsArray = ["bicycle", "pocket", 3, mailBox, twenty, isItRaining, goat];
var result = removeStrings();
Log.Message("stringsArray looks like this after the removal of all the string elements: " + result);
function removeStrings(){
var i;
var x
for(i = 0; i < stringsArray.length; i++){
if (typeof(stringsArray[i]) === 'string'){
x = stringsArray.splice(i, 1);
return x;
}
}
}
}

Version 1, with Array#filter
var a = [1, 2, "3", "4", true];
a = a.filter(function (e) {
return typeof e !== 'string';
});
document.write('<pre>' + JSON.stringify(a, 0, 4) + '</pre>');
Version 2, with Array#splice and running backwards.
var a = [1, 2, "3", "4", true],
i = a.length;
while (i--) {
if (typeof a[i] === 'string') {
a.splice(i, 1);
}
}
document.write('<pre>' + JSON.stringify(a, 0, 4) + '</pre>');

The Array.prototype.filter method is what you need:
var stringsArray = ["bicycle", "pocket", 3, mailBox, twenty, isItRaining, goat];
var result = stringsArray.filter(function(element) {
return typeof element !== 'string';
});

you need to reduce the counter variable and check the original array
try this simple example
var a = [1,2,"3", "4", true];
for( var counter = 0; counter < a.length; counter++)
{
if ( (typeof a[ counter ] ) == "string" )
{
a.splice(counter,1); counter--;
}
}
console.log(a); //output [1, 2, true]

try this code:
function ex06(){
var mailBox = "mailbox";
var twenty = 20;
var isItRaining = true;
var goat = "";
var stringsArray = ["bicycle", "pocket", 3, mailBox, twenty, isItRaining, goat];
var result = removeStrings();
Log.Message("stringsArray looks like this after the removal of all the string elements: " + result);
function removeStrings(){
var newarray = [];
var i;
var x
for(i = 0; i < stringsArray.length; i++){
if (typeof(stringsArray[i]) !== 'string'){
newarray.push(stringsArray[i]);
}
}
return newarray
}
}

JavaScript offers native methods to filter arrays, so that you can remove string elements more easily: Array.prototype.filter can make the process a lot easier (and prevents strange behaviours when using splice inside a loop).
function ex06(){
var mailBox = "mailbox";
var twenty = 20;
var isItRaining = true;
var goat = "";
var stringsArray = ["bicycle", "pocket", 3, mailBox, twenty, isItRaining, goat];
var result = removeStrings(stringsArray);
Log.Message("stringsArray looks like this after the removal of all the string elements: " + result);
function removeStrings(arrayWithString){
return arrayWithString.filter(function(item) {
return typeof item !== 'string'; // returns only items which are not strings
});
}
}
A small piece of advice: Pass in the array into your function instead of referencing it from the parent scope. This way you have a pure, reusable function (and no strange side effects you might not want).

I assume this is an exercise, and that's why you're not using Array#filter.
The problem is that you have your return x inside your for loop, so you return the first string you find.
You have at least three options:
Don't return anything, since removeStrings is modifying the original array. That one's easy: Just remove the return x; line.
Don't modify the original array; instead, create and return a new array with the strings left out. In that case, you'd start with x = [] before the loop, remove the splice call, and instead push any non-string onto x.
Modify the original array, and create and return a new array containing the strings you've removed. In that case, you'd remove return x from inside the loop, have x = [] before the loop, and push the entries you remove onto x. Then return x at the end.
In any of the places where you're modifying the original, note gurvinder372's point that when you remove an entry, you need to not increase the index counter, as you'll end up skipping the next entry.
I wouldn't do it the way he suggests, though; when I'm looping through an array modifying it, for isn't what I reach for, I reach for while:
i = 0;
while (i < stringsArray.length) {
if (typeof stringsArray[i] === 'string'){
stringsArray.splice(i, 1);
// We leave `i` alone here, because we need to process
// the new `stringsArray[i]` on the next pass
} else {
// Didn't remove this entry, move past it
++i;
}
}
Side note: typeof isn't a function, it's an operator, there's no need to put its operand in ():if (typeof stringsArray[i] === 'string'){

Duplicate-free version of array of objects

I implemented a function that creates a duplicate-free version of an array, but it doesn't work for array of objects. I don't understand and I can't find information how to fix it.
My function:
function uniq(array) {
var length = array.length;
if (!length) {
return;
}
var index = 0;
var result = [];
while (index < length) {
var current = array[index];
if (result.indexOf(current) < 0) {
result.push(current);
}
index++;
}
return result;
}
Example:
var my_data = [
{
"first_name":"Bob",
"last_name":"Napkin"
},
{
"first_name":"Billy",
"last_name":"Joe"
},
{
"first_name":"Billy",
"last_name":"Joe",
}
]
uniq([1, 1, 2, 3]) // => [1, 2, 3]
uniq(my_data) // => [ { "first_name":"Bob", "last_name":"Napkin" }, { "first_name":"Billy", "last_name":"Joe" }, { "first_name":"Billy", "last_name":"Joe" } ]
Do you know someone how to creates a duplicate-free version of array of objects?

indexOf() in javascript does not perform a deep comparison of objects. On top of that, any two objects that are created will never be "equal" to each other. If you do:
var a = {};
var b = {};
a == b; //false
a === b; //false
You need to perform a deep comparison against all values (if that's even what you're looking to do, because there could be other equalities you're looking for). I won't go into how to do a deep comparison because, well, Google.

A solution if the objects are not huge, the array doesn't have a huge amount of elements and if the objects don't contain reference loops is to use JSON.stringify to decide if two objects are equal...
function uniq(A) {
var seen = {};
var result = [];
A.forEach(function(x) {
var str = "" + JSON.stringify(x);
if (!seen[str]) {
seen[str] = 1;
result.push(x);
}
});
return result;
}

Since these objects are simply used for data storage (i.e. they don't have methods or prototype extensions and such applied to them), I might suggest serializing and hashing each object in the array and storing the hashes in an object for determination of uniqueness. Now the question is which hashing function to use. There are a number of md5 and SHA-256 implementations available (search StackOverflow for this). My example will just assume the existence of a hash function called hashFunction().
function uniqArrayObjects(array) {
// make sure we have an array
if(Array.isArray(array) === false) {
console.log('Doh! No array passed.');
return null;
}
var length = array.length;
// you can return input array if it has 0 or 1 items in it
// it is already unique
if (length === 0 || length === 1) {
return array;
}
// object for storing hashes
var hashTable = {};
// filter and return the array
return array.filter(function(obj) {
var json = JSON.stringify(obj);
var hash = hashFunction(json);
if (typeof hashTable[hash] === undefined) {
// this item doesn't exist in hash table yet
// add to hash table and return true to add this to filtered result
hashTable[hash] = 1; // value doesn't matter here
return true;
} else {
return false;
}
});
}

Access JavaScript property case-insensitively?

Assume I have an object:
var obj = {
foo:"bar",
fizz:"buzz"
};
I need to access a property of that object dynamically like so:
var objSetter = function(prop,val){
obj[prop] = val;
}
No problems there, except for that prop needs to be case insensitive in case the property name is passed into the function as, say, Foo instead of foo.
So how can I point to an object's property by name without regard to case? I would like to avoid iterating the entire object if possible.

Try this:
var myObject = { "mIxeDCaSEKeY": "value" };
var searchKey = 'mixedCaseKey';
var asLowercase = searchKey.toLowerCase();
myObject[Object.keys(myObject).find(key => key.toLowerCase() === asLowercase)];
You can alternatively already provide the searchKey in lowercase.
If you want it as a function:
/**
* #param {Object} object
* #param {string} key
* #return {any} value
*/
function getParameterCaseInsensitive(object, key) {
const asLowercase = key.toLowerCase();
return object[Object.keys(object)
.find(k => k.toLowerCase() === asLowercase)
];
}
If the key can't be found, then it'll return undefined, just like normal.
If you need to support older browsers, then you can use filter instead:
function getParameterCaseInsensitive(object, key) {
const asLowercase = key.toLowercase();
return object[Object.keys(object).filter(function(k) {
return k.toLowerCase() === asLowercase;
})[0]];
}
I suggest using the polyfills for Object.keys() and Array.filter() if you need even older support.
Note: If you want to also check non-enumerable keys, use Object.getOwnPropertyNames() instead of Object.keys().
Nerdy Note: This assumes your Object doesn't have a key undefined (eg: const foo = {[undefined]: 'bar'};). That's just weird.

Compare all the properties of obj with prop.
var objSetter = function(prop,val){
prop = (prop + "").toLowerCase();
for(var p in obj){
if(obj.hasOwnProperty(p) && prop == (p+ "").toLowerCase()){
obj[p] = val;
break;
}
}
}

For this, I prefer using the prototype over a standalone function just for ease of use and expressiveness. I just don't like funneling objects into functions if I don't have to.
Also, while the accepted answer works, I wanted a more comprehensive solution for both getting and setting that would behave as much like the native dot notation or bracket notation as possible.
With that in mind, I created a couple prototype functions for setting/getting an object property without regard to case. You have to remember to be VERY responsible when adding to the Object prototype. Especially when using JQuery and other libraries. Object.defineProperty() with enumerable set to false was used specifically to avoid conflict with JQuery. I also didn't bother naming the functions anything that indicates they are case-insensitive, but you certainly could. I like shorter names.
Here's the getter:
Object.defineProperty(Object.prototype, "getProp", {
value: function (prop) {
var key,self = this;
for (key in self) {
if (key.toLowerCase() == prop.toLowerCase()) {
return self[key];
}
}
},
//this keeps jquery happy
enumerable: false
});
Here's the setter:
Object.defineProperty(Object.prototype, "setProp", {
value: function (prop, val) {
var key,self = this;
var found = false;
if (Object.keys(self).length > 0) {
for (key in self) {
if (key.toLowerCase() == prop.toLowerCase()) {
//set existing property
found = true;
self[key] = val;
break;
}
}
}
if (!found) {
//if the property was not found, create it
self[prop] = val;
}
return val;
},
//this keeps jquery happy
enumerable: false
});
Now that we've created those functions, our code is super clean and concise and just works.
Case-insensitive getting:
var obj = {foo: 'bar', camelCase: 'humpy'}
obj.getProp("FOO"); //returns 'bar'
obj.getProp("fOO"); //returns 'bar'
obj.getProp("CAMELCASE"); //returns 'humpy'
obj.getProp("CamelCase"); //returns 'humpy'
Case-insensitive setting:
var obj = {foo: 'bar', camelCase: 'humpy'}
obj.setProp('CAmelCasE', 'super humpy'); //sets prop 'camelCase' to 'super humpy'
obj.setProp('newProp', 'newval'); //creates prop 'newProp' and sets val to 'newval'
obj.setProp('NewProp', 'anotherval'); //sets prop 'newProp' to 'anotherval'

Yet another variation on those already presented which pushes the iteration down into the Underscore/Lodash findKey function:
var _ = require('underscore');
var getProp = function (obj, name) {
var realName = _.findKey(obj, function (value, key) {
return key.toLowerCase() === name.toLowerCase();
});
return obj[realName];
};
For example:
var obj = { aa: 1, bB: 2, Cc: 3, DD: 4 };
getProp(obj, 'aa'); // 1
getProp(obj, 'AA'); // 1
getProp(obj, 'bb'); // 2
getProp(obj, 'BB'); // 2
getProp(obj, 'cc'); // 3
getProp(obj, 'CC'); // 3
getProp(obj, 'dd'); // 4
getProp(obj, 'DD'); // 4
getProp(obj, 'EE'); // undefined

This answer requires ES6.
const x = { 'aB': 1, 'X-Total-Count': 10, y3: 2 }
console.log(x[Object.keys(x).find(key=>{return key.match(/^ab$/i)})])
console.log(x[Object.keys(x).find(key=>{return key.match(/^x-total-count$/i)})])
console.log(x[Object.keys(x).find(key=>{return key.match(/^y3$/i)})])

It seems to me like a good candidate for Proxy with traps to convert string keys to either upper case or lower case and behaving like a regular object.
This works with either notation: dots or braquets
Here is the code:
'use strict';
function noCasePropObj(obj)
{
var handler =
{
get: function(target, key)
{
//console.log("key: " + key.toString());
if (typeof key == "string")
{
var uKey = key.toUpperCase();
if ((key != uKey) && (key in target))
return target[key];
return target[uKey];
}
return target[key];
},
set: function(target, key, value)
{
if (typeof key == "string")
{
var uKey = key.toUpperCase();
if ((key != uKey) && (key in target))
target[key] = value;
target[uKey] = value;
}
else
target[key] = value;
},
deleteProperty: function(target, key)
{
if (typeof key == "string")
{
var uKey = key.toUpperCase();
if ((key != uKey) && (key in target))
delete target[key];
if (uKey in target)
delete target[uKey];
}
else
delete target[key];
},
};
function checkAtomic(value)
{
if (typeof value == "object")
return new noCasePropObj(value); // recursive call only for Objects
return value;
}
var newObj;
if (typeof obj == "object")
{
newObj = new Proxy({}, handler);
// traverse the Original object converting string keys to upper case
for (var key in obj)
{
if (typeof key == "string")
{
var objKey = key.toUpperCase();
if (!(key in newObj))
newObj[objKey] = checkAtomic(obj[key]);
}
}
}
else if (Array.isArray(obj))
{
// in an array of objects convert to upper case string keys within each row
newObj = new Array();
for (var i = 0; i < obj.length; i++)
newObj[i] = checkAtomic(obj[i]);
}
return newObj; // object with upper cased keys
}
// Use Sample:
var b = {Name: "Enrique", last: "Alamo", AdDrEsS: {Street: "1233 Main Street", CITY: "Somewhere", zip: 33333}};
console.log("Original: " + JSON.stringify(b)); // Original: {"Name":"Enrique","last":"Alamo","AdDrEsS":{"Street":"1233 Main Street","CITY":"Somewhere","zip":33333}}
var t = noCasePropObj(b);
console.log(JSON.stringify(t)); // {"NAME":"Enrique","LAST":"Alamo","ADDRESS":{"STREET":"1233 Main Street","CITY":"Somewhere","ZIP":33333}}
console.log('.NaMe:' + t.NaMe); // .NaMe:Enrique
console.log('["naME"]:' + t["naME"]); // ["naME"]:Enrique
console.log('.ADDreSS["CitY"]:' + t.ADDreSS["CitY"]); // .ADDreSS["CitY"]:Somewhere
console.log('check:' + JSON.stringify(Object.getOwnPropertyNames(t))); // check:["NAME","LAST","ADDRESS"]
console.log('check2:' + JSON.stringify(Object.getOwnPropertyNames(t['AddresS']))); // check2:["STREET","CITY","ZIP"]

You could do this in order to "normalize" prop
var normalizedProp = prop.toLowerCase();
obj[normalizedProp] = val;

const getPropertyNoCase = (obj, prop) => obj[Object.keys(obj).find(key => key.toLowerCase() === prop.toLowerCase() )];
or
const getPropertyNoCase = (obj, prop) => {
const lowerProp = prop.toLowerCase(obj[Object.keys(obj).find(key => key.toLowerCase() === prop.toLowerCase() )];
}

The ES6 example posted by #nilloc is incorrect and will break in use.
Here is a working example:
const x = {'first':5,'X-Total-Count':10,'third':20};
console.log(x[Object.keys(x).reduce((result,key)=>{
if (!result) {
return key.match(/x-total-count/i)
} else {
return result;
}
},null)]);
or better yet, it should return undefined if the key doesn't exist:
const x = {'first':5,'X-Total-Count':10,'third':20};
console.log(x[Object.keys(x).reduce((result,key)=>{
if (!result) {
return key.match(/x-total-count/i) || undefined
} else {
return result;
}
},undefined)]);
One consideration is that the above example will return the last matching key in the object if there are multiple keys that match.
Here is an example with the code made into a function:
/**
* #param {Object} object
* #param {string} key
* #return {string||undefined} value || undefined
*/
function getKeyCase(obj,key) {
const re = new RegExp(key,"i");
return Object.keys(obj).reduce((result,key)=>{
if (!result) {
return key.match(re) || undefined
} else {
return result;
}
},undefined);
const x = {'first':5,'X-Total-Count':10,'third':20};
console.log(x[getKeyCase(x,"x-total-count")]);

Its really sad that the iteration can't be skipped as it seems. For me what is acceptable but may not be for everyone is to shape the object one time via iteration and then use it in regular hashmap fashion.
const hashmap = {
'FOO': 'foo as in function programming',
'bar': 'bar is in baz',
};
const shapedmap = Object.entries(hashmap).reduce(
(acc, [key, val]) => (acc[key.toUpperCase()] = val, acc), {}
);
for (const term of ['foo', 'bar', 'baz']) {
const match = shapedmap[term.toUpperCase()]
match && console.log('awesome, we got the term.', match);
};
Even if it just one time lookup has to be performed, it shouldn't less performant as any other iteration solution since after 1 pass, the lookup speed is constant. (I guess).

This is an old question, but it was the first one I found.
As #ZachSmith says, you can use a Proxy.
Here's some example code:
function lowercase(oldKey) {
// Check that it's a string.
return typeof oldKey === 'string' ? oldKey.toLowerCase() : oldKey;
}
const propertiesMap = new Map(
Object.keys(obj).map(propKey => [lowercase(propKey), obj[propKey]])
);
const caseInsensitiveGetHandler = {
get: function(target, property, receiver) {
return propertiesMap.get(lowercase(property));
}
};
obj = new Proxy(obj, caseInsensitiveGetHandler);
For my use case, I only needed to proxy the object's getter, but you may need to implement more of the Proxy methods.

There is no need for any iteration. Since prop might not be a string, it should be coerced to a string first where appropriate since that's what objects do natively. A simple getter function is:
function objGetter(prop) {
return obj[String(prop).toLowerCase()];
}
If there is a requirement is to restring access to own properties:
function objGetter(prop) {
prop = String(prop).toLowerCase();
if (obj.hasOwnProperty(prop)) {
return obj.prop;
}
}
and a setter:
function objSetter(prop, val) {
obj[String(prop).toLowerCase()] = val;
}

Heres a very simple code to do this
Assuming that data is the array of objects like
data=[{"A":"bc","B":"nn"}]
var data=data.reduce(function(prev, curr) {
var cc = curr; // current value
var K = Object.keys(cc); // get all keys
var n = {};
for (var i = 0; i < K.length; i++) {
var key = K[i];//get hte key
n[key.toLowerCase()] = cc[key] // convert to lowercase and assign
}
prev.push(n) // push to array
return prev;
}, [])
Output will be
data=[{"a":"bc","b":"nn"}]

You might only need to do case-insensitive matching (usually expensive because of object iteration) IF a case-sensitive match (cheap and quick) fails.
Say you have:
var your_object = { "Chicago" : 'hi' , "deTroiT" : 'word' , "atlanta" : 'get r dun' } ;
And you have, for whatever reason, the_value, Detroit:
if( your_object.hasOwnProperty( the_value ) )
{
// do what you need to do here
}
else
{ // since the case-sensitive match did not succeed,
// ... Now try a the more-expensive case-insensitive matching
for( let lvs_prop in your_object )
{ if( the_value.toLowerCase() == lvs_prop.toLowerCase() )
{
// do what you need to do here
break ;
} ;
}
} ;

why would we do it that complicated when we simply can make it all lower case:
var your_object = {
"chickago" : 'hi' ,
"detroit" : 'word',
"atlanta" : 'get r dun',
GetName: function (status) {
return this[status].name;
} };
to call it: your_object.GetName(your_var.toLowerCase());

Another simple way:
function getVal(obj, prop){
var val;
prop = (prop + "").toLowerCase();
for(var p in obj){
if(obj.hasOwnProperty(p) && prop == (p+ "").toLowerCase()){
val = obj[p]
break;
}
}
return val;
}
Use it like this:
var obj = {
foo:"bar",
fizz:"buzz"
};
getVal(obj,"FoO") -> returns "bar"

Here is a nice recursive function that allows you to traverse a javascript object in a case-insensitive way:
let testObject = {'a': {'B': {'cC': [1,2,3]}}}
let testSeq = ['a','b','cc']
function keySequence(o, kseq) {
if(kseq.length==0){ return o; }
let validKeys = Object.keys(o).filter(k=>k.toLowerCase()==kseq[0].toLowerCase());
if(validKeys.length==0) { return `Incorrect Key: ${kseq[0]}` }
return keySequence(o[validKeys[0]], kseq.slice(1))
}
keySequence(testObject, testSeq); //returns [1,2,3]

This will convert everything to lowercase, but in a bind this could help if you are not concerned with retaining case.
var somedata = {
"MixEdCase": 1234
}
var temp = JSON.parse(JSON.stringify(somedata).toLowerCase());
console.log(temp.mixedcase);
// or
console.log(temp["mixedcase"]);

So, you will need to get the object key that matches the case of the existing object, then use this to do your object update.
const obj = {
foo:"bar",
fizz:"buzz"
};
// to get obj.foo or obj.FOO or obj.foO returning "bar"
// create regex expression of case insensitive version of the key string
const regex=passedKey=> new RegExp(`^${passedKey}$`,'gi');
// find the key that matches the string you are passing
const formattedKey=passedKey=>Object.keys(obj).find(key=>regex(passedKey).test(key));
formattedKey('Foo'); // returns foo
formattedKey('FoO'); // returns foo
// consequently you can can use it like wise
obj[formattedKey('Foo')] // returns bar
obj[formattedKey('FoO')] // returns bar
obj[formattedKey('foo')] // returns bar

Find duplicates without going through the list twice?

I need to know if one or more duplicates exist in a list. Is there a way to do this without travelling through the list more than once?
Thanks guys for the suggestions. I ended up using this because it was the simplest to implement:
var names = [];
var namesLen = names.length;
for (i=0; i<namesLen; i++) {
for (x=0; x<namesLen; x++) {
if (names[i] === names[x] && (i !== x)) {alert('dupe')}
}
}

Well the usual way to do that would be to put each item in a hashmap dictionary and you could check if it was already inserted. If your list is of objects they you would have to create your own hash function on the object as you would know what makes each one unique. Check out the answer to this question.
JavaScript Hashmap Equivalent

This method uses an object as a lookup table to keep track of how many and which dups were found. It then returns an object with each dup and the dup count.
function findDups(list) {
var uniques = {}, val;
var dups = {};
for (var i = 0, len = list.length; i < len; i++) {
val = list[i];
if (val in uniques) {
uniques[val]++;
dups[val] = uniques[val];
} else {
uniques[val] = 1;
}
}
return(dups);
}
var data = [1,2,3,4,5,2,3,2,6,8,9,9];
findDups(data); // returns {2: 3, 3: 2, 9: 2}
var data2 = [1,2,3,4,5,6,7,8,9];
findDups(data2); // returns {}
var data3 = [1,1,1,1,1,2,3,4];
findDups(data3); // returns {1: 5}
Since we now have ES6 available with the built-in Map object, here's a version of findDups() that uses the Map object:
function findDups(list) {
const uniques = new Set(); // set of items found
const dups = new Map(); // count of items that have dups
for (let val of list) {
if (uniques.has(val)) {
let cnt = dups.get(val) || 1;
dups.set(val, ++cnt);
} else {
uniques.add(val);
}
}
return dups;
}
var data = [1,2,3,4,5,2,3,2,6,8,9,9];
log(findDups(data)); // returns {2 => 3, 3 => 2, 9 => 2}
var data2 = [1,2,3,4,5,6,7,8,9];
log(findDups(data2)); // returns empty map
var data3 = [1,1,1,1,1,2,3,4];
log(findDups(data3)); // returns {1 => 5}
// display resulting Map object (only used for debugging display in snippet)
function log(map) {
let output = [];
for (let [key, value] of map) {
output.push(key + " => " + value);
}
let div = document.createElement("div");
div.innerHTML = "{" + output.join(", ") + "}";
document.body.appendChild(div);
}

If your strings are in an array (A) you can use A.some-
it will return true and quit as soon as it finds a duplicate,
or return false if it has checked them all without any duplicates.
has_duplicates= A.some(function(itm){
return A.indexOf(itm)===A.lastIndexOf(itm);
});

If your list was just words or phrases, you could put them into an associative array.
var list=new Array("foo", "bar", "foobar", "foo", "bar");
var newlist= new Array();
for(i in list){
if(newlist[list[i]])
newlist[list[i]]++;
else
newlist[list[i]]=1;
}
Your final array should look like this:
"foo"=>2, "bar"=>2, "foobar"=>1