JavaScript

When writing asynchronous code, it is possible to create subtle race condition bugs. Consider the following example:

It is considered a best practice to avoid 'polluting' the global scope with variables that are intended to be local to the script. Global variables created from a script can produce name collisions with global variables created from another script, which will usually lead to runtime errors or unexpected behavior. It is mostly useful for browser scripts.

Comparing to null without a type-checking operator (=== or !==), can have unintended results as the comparison will evaluate to true when comparing to not just a null, but also an undefined value.

In JavaScript, you can extend any object, including builtin or "native" objects. Sometimes people change the behavior of these native objects in ways that break the assumptions made about them in other parts of the code.

Using promises is forbidden in places where the TypeScript compiler allows them but they are not handled properly. These situations can often arise due to a missing await keyword or just a misunderstanding of the way async functions are handled/awaited.

DisplayName allows you to name your component. This name is used by React in debugging messages.

'^([A-Z][a-z0-9]*)+Type$$' is the default pattern for type alias names.

React components use JSX, not HTML. So we need to use JSX attributes and React replicate the respective HTML property/attribute while rendering. Use of HTML property in JSX can sometimes lead to errors. For example, class is a keyword in JavaScript (JSX is an extension of JavaScript), so it will throw an error. However, in HTML it is a valid attribute.

Note: If you use React with Web Components, use the class attribute instead.

Some code paths are unreachable because the return, throw, break, and continue statements unconditionally exit a block of code. The code statements after the above keywords (which exit the code block) will not execute.

__proto__ property has been deprecated as of ECMAScript 3.1 and shouldn't be used. Use Object.getPrototypeOf and Object.setPrototypeOf instead.

When creating a JSX element with a tag, it is often desired to have the link open in a new tab using the target='_blank' attribute. Using this attribute unaccompanied by rel='noreferrer', however, is a severe security vulnerability.

The result of a call to String#toUpperCase should only be compared with an uppercase string. Calls like s.toUpperCase() === "Not-Uppercase" will always evaluate to false. Similarly, calls to toLowerCase should only be compared with lowercase strings.

Located potential errors resulting from misspellings of variable and parameter names, or accidental implicit globals.

Arrow functions should not be used in computed properties because they are unable to access other properties (using this.property) of the same object. Accidental usage can thus lead to bugs.

Avoid using .on() in favour of component's lifecycle hooks. The order of execution for on() is not deterministic.

Nesting JSX elements too deeply can confuse developers reading the code. To make maintenance and refactoring easier, DeepSource recommends limiting the maximum JSX tree depth to 4.

Function declarations (with the function keyword) and variable declarations should preferably be in the root of a program or the body of a function. Having nested function declarations inside blocks may have unexpected results at runtime due to hoisting.

ember-data has been split in multiple packages. For instance, its store is now released in @ember-data/store package. These packages have been released starting from ember-data version 3.11.

Why we have to migrate?

• Reduce Confusion & Bike Shedding
• Improve The TypeScript Experience
• Simplify The Mental Model
• Provide a Clear Subdivision of Packages

Setting webSecurity property to false, or allowRunningInsecureContent to true in an Electron renderer process like BrowserWindow or BrowserView disables crucial security features. By default, the webSecurity property is always true and the allowRunningInsecureContent property is always false.

Certificate validation is an important aspect of Transport Layer Security (TLS) connections as it helps to ensure the authenticity and integrity of the data being transmitted. Disabling certificate validation can lead to several security risks, including Man-in-the-Middle Attacks. Without certificate validation, it is possible for an attacker to intercept the communication and present a fake certificate to the client.