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Using string interpolation in React.js regex function

I am having some issues using string interpolation in a regex, however I have also tried to log it to the console and I can see that I am doing it incorrectly.
I am trying to loop through an array of weather types to see if my API request returned a type of weather which requires me to add a class to one of my elements in the UI.
I iniitally thought the issue was using array[x] in the regex, but I have assigned this to a variable p and am still getting the same result.
let weatherTypes = ['rain', 'clouds', 'snow', 'clear', 'thunderstorm'];
for (var x= 0; x <= weatherTypes.length; x++) {
let p = weatherTypes[x];
console.log(p)
var searchPattern = `/${p}/i`;
var result = this.state.description.match(searchPattern);
console.log(`splash--weather-${p}`);
if(result !== null) {
var element = document.getElementById("splashContact");
element.classList.add(`splash--weather-${weatherTypes[0]}` );
}
}
The logic to add the class works when I abstract it out of the for loop so I know that part is working fine.
Can somebody please point me in the right direction?
edit Have now used backticks instead of quotation marks

searchPattern is a string so you just need to use the RegExp constructor before using it.
var searchPattern = `${p}/i`;
var searchPatternRegex = RegExp(`${searchPattern}`);

How to get json value by string?

I receive the following string from the server response：
var jsonData = '[{"firstName":"Bill","lastName":"Gates"},{"firstName":"George","lastName":"Bush"},{"firstName":"Thomas","lastName":"Carter"}]';
I see some jquery plugins can predefine the keys they want
like: index:"firstName", and they get a ul like
<li>Bill</li>
<li>George</li>
<li>Thomas</li>
If index:"lastName", they get a ul like
<li>Gates</li>
<li>Bush</li>
<li>Carter</li>
The only way I know how to parse a json format string is:
var object = JSON.parse(jsonData);
var firstName = object[i].firstName;
var lastName= object[i].lastName;
The plugin pass the index like a parameter
function f(index) {
return object[i].index;
}
How can they achieve this？
Thanks for helping!

You can access object properties with square brackets. JS objects work like arrays in this regard.
var objects = JSON.parse(jsonData),
key = "firstName";
objects.forEach(function (obj) {
var value = obj[key];
// ...
});

How to get the 'Value' using 'Key' from json in Javascript/Jquery

I have the following Json string. I want to get the 'Value' using 'Key', something like
giving 'BtchGotAdjust' returns 'Batch Got Adjusted';
var jsonstring=
[{"Key":"BtchGotAdjust","Value":"Batch Got Adjusted"},{"Key":"UnitToUnit","Value":"Unit To Unit"},]

Wow... Looks kind of tough! Seems like you need to manipulate it a bit. Instead of functions, we can create a new object this way:
var jsonstring =
[{"Key":"BtchGotAdjust","Value":"Batch Got Adjusted"},{"Key":"UnitToUnit","Value":"Unit To Unit"},];
var finalJSON = {};
for (var i in jsonstring)
finalJSON[jsonstring[i]["Key"]] = jsonstring[i]["Value"];
You can use it using:
finalJSON["BtchGotAdjust"]; // Batch Got Adjusted

As you have an array in your variable, you have to loop over the array and compare against the Key-Property of each element, something along the lines of this:
for (var i = 0; i < jsonstring.length; i++) {
if (jsonstring[i].Key === 'BtchGotAdjust') {
console.log(jsonstring[i].Value);
}
}
By the way, I think your variable name jsonstring is a little misleading. It does not contain a string. It contains an array. Still, the above code should give you a hint in the right direction.

Personally I would create a map from the array and then it acts like a dictionary giving you instantaneous access. You also only have to iterate through the array once to get all the data you need:
var objectArray = [{"Key":"BtchGotAdjust","Value":"Batch Got Adjusted"},{"Key":"UnitToUnit","Value":"Unit To Unit"}]
var map = {}
for (var i=0; i < objectArray.length; i++){
map[objectArray[i].Key] = objectArray[i]
}
console.log(map);
alert(map["BtchGotAdjust"].Value)
alert(map["UnitToUnit"].Value)
See js fiddle here: http://jsfiddle.net/t2vrn1pq/1/

Create JSON string from javascript for loop

I want to create a JSON string from a javascript for loop. This is what I tried to do (which gives me something that looks like a JSON string), but it does not work.
var edited = "";
for(var i=1;i<POST.length-1;i++) {
edited += '"'+POST[i].name+'":"'+POST[i].value+'",';
}
It gives me this:
"type":"empty","name":"email-address","realname":"Email Address","status":"empty","min":"empty","max":"empty","dependson":"empty",
This does not work if I try to convert it into a JSON object later.

Two problems:
You want an object, so the JSON string has to start with { and end with }.
There is a trailing , which may be recognized as invalid.
It's probably better to use a library, but to correct your code:
Change var edited = ""; to var edited = "{"; to start your JSON string with a {
Add edited = edited.slice(0, -1); after the for loop to remove the trailing comma.
Add edited += "}"; after the previous statement to end your JSON string with a }
Your final code would be:
var edited = "{";
for(var i=1;i<POST.length-1;i++) {
edited += '"'+POST[i].name+'":"'+POST[i].value+'",';
}
edited = edited.slice(0, -1);
edited += "}";
Again, it's best to use a library (e.g. JSON.stringify) by making an object with a for loop, adding properties by using POST[i].name as a key and POST[i].value as the value, then using the library to convert the object to JSON.
Also, you are starting with index 1 and ending with index POST.length-2, therefore excluding indices 0 (the first value) and POST.length-1 (the last value). Is that what you really want?

//dummy data
var post=[{name:'name1',value:1},{name:'name2',value:2}];
var json=[];
for(var i=0;i<post.length;i++)
{
var temp={};
temp[post[i].name]=post[i].value;
json.push(temp);
}
var stringJson = JSON.stringify(json);
alert(stringJson );
http://jsfiddle.net/3mYux/

You have extra comma in your JSON string. JSON string format: {"JSON": "Hello, World"}
var edited = "{";
for(var i=1;i<POST.length-1;i++) {
edited += '"'+POST[i].name+'":"'+POST[i].value+'",';
}
// remove last comma:
edited = edited.substring(0, edited.length-1) + "}";

Can't you just build up a hash and do toString on the hash? Something like this:
var edited = {};
for(var i=0;i<POST.length-1;i++) {
edited[POST[i].name] = POST[i].value;
}
Or maybe JSON.stringify is what you are looking for: http://www.json.org/js.html

How do I access a JSON object using a javascript variable

What I mean by that is say I have JSON data as such:
[{"ADAM":{"TEST":1}, "BOBBY":{"TEST":2}}]
and I want to do something like this:
var x = "ADAM";
alert(data.x.TEST);

var data = [{"ADAM":{"TEST":1}, "BOBBY":{"TEST":2}}],
x = "ADAM";
alert(data[0][x].TEST);
http://jsfiddle.net/n0nick/UWR9y/

Since objects in javascripts are handled just like hashmaps (or associative arrays) you can just do data['adam'].TEST just like you could do data.adam.TEST. If you have a variable index, just go with the [] notation.
var data = [{"ADAM":{"TEST":1}, "BOBBY":{"TEST":2}}]
alert(data[0].ADAM.TEST);
alert(data[0]['ADAM'].TEST)
if you just do
var data = {"ADAM":{"TEST":1}, "BOBBY":{"TEST":2}};
you could access it using data.ADAM.TEST and data['ADAM'].TEST

That won't work as you're setting x to be a string object, no accessing the value from your array:
alert(data[0]["ADAM"].TEST);

var data = [{"ADAM":{"TEST":1}, "BOBBY":{"TEST":2}}],
x = "ADAM";
alert(data[x].TEST);
This is what worked for me. This way you can pass in a variable to the function and avoid repeating you code.
function yourFunction(varName, elementName){
//json GET code setup
document.getElementById(elementName).innerHTML = data[varName].key1 + " " + data.[varName].key2;
}