ReSharper 2021.2 Help

Code Inspection and Quick-Fixes in TypeScript

The key features of ReSharper's code analysis are also supported in TypeScript. You can find the detailed information on these features in the corresponding topics of the Code analysis section. In the main topic of the section, you can also find the feature matrix and check what exactly is supported in TypeScript.

In this topic, you can find some examples of using code analysis features in TypeScript.

Code Inspection

ReSharper's code inspection detects compiler errors and other code issues in TypeScript files. By default, TypeScript code is inspected in design time. If necessary, you can also run code inspection in specific scope:

ReSharper: Inspecting TypeScript issues in specific scope

Code inspection behavior as well as code generation results depend on the TypeScript project settings. In Visual Studio 2013 and later, you can configure the first two of this settings in the project property editor (right-click the project and choose Properties). In Visual Studio 2012, you can only change these properties manually by editing the project file .csproj.

TargetEsVersion (ECMAScript version)
If the version is lower than 5, ReSharper detects usages of get and set as errors. If the version is 5 or greater, then ReSharper detects octal literals as errors and suggests replacing them with hexadecimal or decimal literals.
NotImplicitAny (Allow implicit 'any' types)
Depending on this property, ReSharper either detects implicit 'any' types (for example var a; a = 5;) as errors or not.
TypeScriptNoResolve
If this option is set to 'true', ReSharper detects usages of external modules as errors.

Code inspection behavior also depends on the options configured on the Code Editing | TypeScript | Syntax Style page of ReSharper options (Alt+R, O). For more information, see Code Style Assistance in TypeScript.

Quick-fixes

Quick-fixes let you automatically resolve most of code issues found with code inspection. If one or more quick-fixes are available for a code issue, you will see the corresponding action indicator when your caret is on the highlighted code. Press Alt+Enter to see and apply the desired fix.

ReSharper provides dozens of quick-fixes for TypeScript. Here are some examples:

Add missing imports

If ReSharper detects types that have not been imported in the current file, it highlights them and suggests to add all missing imports at once. For more information, see Import missing namespaces.

Importing missing namespace in TypeScript

Implement missing members

ReSharper suggests generating non-implemented members automatically:

ReSharper: Implementing interface members in TypeScript

Rename function overload properly

If the names of function overloads are not the same because of a typo, ReSharper highlights mismatching name and suggests a quick-fix:

ReSharper: 'Rename function overload properly' quick-fix in TypeScript

Make public/private

The default member accessibility is public, but if you explicitly specify a function as private, then all its overloads should have the same modifier. If it is not so, ReSharper highlights that and suggests changes.

ReSharper: 'Make public/private' quick-fix in TypeScript

Add type annotation

When type is not specified, the variable is highlighted. Press Alt+Enter to display the list of quick-fixes and apply the following one. Necessary type annotation will be added.

ReSharper: 'Add type annotation' quick-fix in TypeScript

Remove question mark

In TypeScript optional parameters can't have default values. If they by accident have, you can either remove a question mark or remove the initializer.

ReSharper: 'Remove question mark' quick-fix in TypeScript

Remove ambient function body

There is no need to keep unnecessary constructs in your code. In attempt to make code readable, ReSharper suggests removing ambient function bodies, for example.

ReSharper: 'Remove ambient function body' quick-fix in TypeScript

Make ReSharper ignore specific code

To exclude parts of your solution's code from code analysis, navigation, and other features, ReSharper allows you to ignore specific files, folders and file masks in different ways.

To improve performance, ReSharper also automatically detects and starts ignoring large web files that have no references and were probably added to the solution by mistake.

If any of such files are detected, you will see a notification where you can stop ignoring any of those files if you need them for some reason. You can also find all automatically ignored files on the Code Editing | Third-Party Code page of ReSharper options (Alt+R, O).

To stop auto-detection and ignoring large unused web files, clear the Search for web files that can affect performance and exclude them from indexing checkbox on the Code Editing | Third-Party Code page of ReSharper options (Alt+R, O).

Last modified: 23 September 2021