Learners Store

error Error: unable to get local issuer certificate

The error “unable to get local issuer certificate” occurs because Yarn is failing to establish a secure connection due to SSL certificate issues.

Run the following command in your terminal to fix this issue

yarn config set strict-ssl false

After this run the following command

yarn install

If it works, then it is an SSL certificate issue.

Pine Script code for Relative Strength Index (RSI) Calculation

The Relative Strength Index (RSI) can be used for detecting overbought/oversold levels across different timeframes.

Suppose if we want to calculate 14-Period Relative Strength Index (RSI) for 5-minute timeframe, we need to use following pine script code.

rsi_calc = ta.rsi(close, 14)
rsi_5min = request.security(syminfo.tickerid, "5", rsi_calc)

ta.rsi(close, 14) is the built-in function of pine script to calculate 14-Period RSI value using the closing price.

request.security is a function in Pine Script used to retrieve data from different time frames or symbols.

syminfo.tickerid is for getting current symbol/ticker.

As of now we are using “5”, which gives data for 5 minute timeframe. if we want data for 1 minute we need to change it to “1”.

Finally we pass rsi_calc which gives calculated RSI value from the 5-minute timeframe.

Syntax of request.security is as follows

 request.security(symbol, resolution, expression)

You need to enable JavaScript to run this app – After deploying React App to firebase

After deploying React App to Firebase, In Network calls we will see 200 status code but in Response Preview, we will see the message as “You need to enable JavaScript to run this app” . I too faced this issue after deploying my React App to firebase.

In my case issue is with the BASE_URL. Go to your firabse settings and check the config details.

Cross-check with your network call base url with the config details like databaseURL, authDomain. If your network call BASE_URL is not matching with the config details, update your BASE_URL and then deploy the app again. I have fixed my issue by following these steps. If it is not fixing in your case, please follow the proper deployment guidelines.

You can deploy your React App to Firebase by using these instructions : https://learnersstore.com/2024/12/29/deploying-reactjs-app-to-firebase

Deploying ReactJS App to Firebase

Step 1: Install Firebase CLI globally

npm install -g firebase-tools

We can check the version by using the following command

firebase --version

Step 2: Login to the firebase account by using firebase CLI

firebase login

If it is first time then we can navigate to login screen. If already logged in then it will show as “Already logged in “. If you want to login to other account or authenticate again we can use the following command.

firebase login --reauth

Step 3: Initialize firebase in your project’s root directory

firebase init

Then CLI will prompt the following questions.

 Are you ready to proceed? Yes

After proceeding, it will show set of instructions. Navigate through them using Up/Down Arrow keys. Select Hosting by using spacebar.

>(*) Hosting: Configure files for Firebase Hosting and (optionally) set up GitHub Action deploys

Now select the project which you want to use. then it shows as “using project your_project_name”. After that you will see the following questions.

? What do you want to use as your public directory? build

? Configure as a single-page app (rewrite all urls to /index.html)? No

Set up automatic builds and deploys with GitHub? No

 File build/index.html already exists. Overwrite? Yes

firebase.json code should be similar to the following. once check it in your project. if it is missing, rewrites key add it.

{
  "hosting": {
    "public": "build",
    "rewrites": [
      {
        "source": "**",
        "destination": "/index.html"
      }
    ],
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ]
  }
}

Step 4: Build your App using the following command

npm run build

Step 5: Finally delpoy the App to firebase

firebase deploy

TypeScript: Index signature for type ‘string’ is missing in type …

The error “Index signature for type ‘string’ is missing in type” occurs in TypeScript when we are trying to access a property using a dynamic string, but the object type doesn’t define an index signature to accommodate that.

For Example, The above Error will come in the following scenario

index.ts

type Person = {
  name: string;
  age: number;
};

const person: Person = { name: "Joy", age: 20 };

const key = "email";

console.log(person[key]); // Error: Index signature is missing

In the above example, typescript throws an error because key could be any string, but the Person type only explicitly defines name and age. To fix this we can add an index signature to the type as follows.

index.ts

type Person = {
  name: string;
  age: number;
  [key: string]: string // index signature allows only string values
};

const person: Person = { name: "Joy", age: 20, email: "joy@gmail.com" };

const key= "email";

console.log(person[key]); // No Error