Avoid using dot notation with objects and instead use `const` for declaring variables for more

interface obj {
  bar: string
}

function randomFunction() {
  let foo: obj = { bar: "" }
  foo.bar = "hip"
}

let snack: obj = { bar: "" }
snack.bar = "hop"

Upon transcompiling, a warning from tslint pops up:

Identifier 'foo' is never reassigned; use 'const' instead of 'let'. (prefer-const)

Interestingly, the same warning does not occur with the variable snack.

To suppress this warning in the console output, I can use 

/* tslint:disable: prefer-const */

I have not come across any reported bugs on the tslint project. As a newcomer to typescript, I'm left wondering if I am making a mistake here.

typescripttslint

Answer №1

When using tslint, it suggests changing let to const because the variable foo is not being reassigned.

To fix this error, simply use const instead:

const foo: obj = { bar: "" };
foo.bar = "hip";

Keep in mind that using const only prevents reassigning the variable itself:

 const foo = { bar: "" };
 foo = { bar: "" }; // results in an error

It does not make the object immutable.

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

Using Typescript to Encapsulate the Assertion that Foo Belongs to a Specific Type

For the purpose of this demonstration, let's define two dummy classes and include some example code: class X { constructor() {} } class Y extends X { value: number; constructor(value: number) { super(); this.value = valu ...

typescriptassert

Clear pagination - results generated by the clr-dg-page-size component

I'm currently developing an Angular 8 application using Clarity UI. Within my app, I have implemented a datagrid with pagination. My challenge lies in fetching data after changing the number of items per page, as there is no output provided by the Cl ...

angulartypescriptdatagridvmwareclarity

Obtain a string of characters from different words

I have been trying to come up with a unique code based on the input provided. Input = "ABC DEF GHI" The generated code would look like, "ADG" (first letter of each word) and if that is taken, then "ABDG" (first two letters o ...

javascriptangulartypescript

The 'in' operator is unable to find 'colour' within true (function return type)

Here's the TypeScript code I'm working with: let a: unknown = true; if(hasColour(a)) { console.log(a.colour); // Using a.colour after confirming a has the colour property } I've created a function to check if the color property exist ...

typescript

Learn how to implement AuthContext and createDataContext in React Native Expo development using TypeScript

AuthContext.tsx import createDataContext from './createDataContext'; import serverApi from '../api/server'; const authReducer = ({state, action}: any) => { switch(action.type){ default: return state; } } ...

reactjstypescriptreact-native

Tips for iterating through an observable using the .subscribe method

I am currently working on a function that involves looping and using .subscribe to receive an array object each time, with the intention of later pushing this data into another array. The loop itself is functional; however, there is an issue with the resul ...

angulartypescriptrxjs

Tips for utilizing MUI Typography properties in version 5

I'm clear on what needs to be done: obtain the type definition for Typography.variant. However, I'm a bit uncertain on how to actually get these. interface TextProps { variant?: string component?: string onClick?: (event: React.MouseEvent&l ...

javascriptreactjstypescriptmaterial-ui

Automatically update data in Angular without the need to refresh the page

One feature of my application involves displaying a table with rows retrieved from a database. The functionality responsible for fetching this data is an AJAX call, implemented as follows: getPosts(): Observable<Posts[]> { return this.http.post ...

javascriptajaxangulartypescriptdynamic

Sending data from the LoginComponent to the RootComponent

I am facing a challenge with implementing *ngIf to hide the login/logout option in the navbar based on the user's authentication status. When logged in, I want to hide the logout link. Here is my current setup. app.component.ts import { Component, O ...

angulartypescript

What could be causing the delay in loading http requests in Angular?

When attempting to update the array value, I am encountering an issue where it works inside the httpClient method but not outside of it. How can this be resolved in Angular 14? Here is a snippet from app.component.ts: ngOnInit(): void { this.httpC ...

angulartypescriptangular14

The use of findDOMNode has been marked as outdated in StrictMode. Specifically, findDOMNode was utilized with an instance of Transition (generated by MUI Backdrop) that is contained

I encountered the following alert: Alert: detectDOMNode is now outdated in StrictMode. detectDOMNode was given an instance of Transition which resides within StrictMode. Instead, attach a ref directly to the element you wish to reference. Get more inform ...

reactjstypescriptmaterial-ui

Troubleshooting issue with applying hover effect to child divs

How come when I hover over one of the child items in my parentDiv, the background of the last childDiv changes no matter which child I place my mouse on? for (let i = 0; i < Number(height); i++) { for (let j = 0; j < Number(width); j++ ...

javascripthtmlcsstypescript

Bringing in TypeScript from external Node packages

I am looking to organize my application by splitting it into separate node modules, with a main module responsible for building all other modules. Additionally, I plan to use TypeScript with ES6 modules. Below is the project structure I have in mind: ma ...

node.jstypescript

Definition of Promise resolve type in Visual Code's d.ts file

Need help with: // api.js export function getLayout(){ return axios.get('/api/layout').then(res => res.data) } // api.d.ts declare interface JSONResponse { meta: object, data: Array<Field> } export declare function getLayout ...

typescripttypescript-typingsvisual-studio-code

What is the key to mastering any concept in Angular2 for optimal results?

When creating a Pipe to filter data, I often use the datatype any, allowing for flexibility with types. However, I have some questions regarding this approach: Is it considered a best practice? Does it impact performance when handling large amounts of da ...

angulartypescript

What is the best approach for determining the most effective method for invoking a handler function in React?

As a newcomer to React, I am navigating through the various ways to define callback functions. // Approach 1 private handleInputChange = (event) => { this.setState({name: event.target.value}); } // Approach 2 private handleInputChange(event){ t ...

javascriptreactjstypescript

Is there a way to delegate properties in Angular 2+ similar to React?

When working with React, I have found it convenient to pass props down dynamically using the spread operator: function SomeComponent(props) { const {takeOutProp, ...restOfProps} = props; return <div {...restOfProps}/>; } Now, I am curious how I ...

javascriptangularreactjstypescript

Struggling to implement a singleton service in Angular as per the documentation provided

I have implemented a service in Angular that I want to be a singleton. Following the guidelines provided in the official documentation, I have set the providedIn property to "root" as shown below: @Injectable({ providedIn: "root" }) export class SecuritySe ...

angulartypescriptdependency-injectionsingletonangular8

Ways to break down a collection of multiple arrays

Looking to transform an array that consists of multiple arrays into a format suitable for an external API. For example: [ [44.5,43.2,45.1] , [42, 41.2, 48.1] ] transforming into [ [44.5,42], [43.2,41.2] , [45.1, 48.1] ] My current code attempts this ...

javascripttypescript

Resolving Node.js Absolute Module Paths with TypeScript

Currently, I am facing an issue where the modules need to be resolved based on the baseUrl so that the output code is compatible with node.js. Here is my file path: src/server/index.ts import express = require('express'); import {port, database ...

javascriptnode.jstypescriptnode-modules