JSEval

With the JSEval plugin you can inspect the evaluation results of your code exactly at the position they appear in a JavaScript or a TypeScript file. The tool allows for inspecting values from console.log expressions as well as from expressions with appended //? comments before an expression is reached.

Additionally, you can further change the context of the execution by selecting a runtime, specifying environment variables and application parameters, configuring TypeScript handling, and more.

Live evaluations and code coverage

With JSEval, you can inspect your code on the fly, receiving live updates to evaluations and code coverage as your program is executing. The value of an expression is visible in the editor directly when it becomes available or is executed.

To inspect the value of an expression

Append a //? comment at the end of the expression.
Alternatively, log the value to the console by using one of the following error methods:
- console.log()
- console.error()
- console.trace()
- console.info()
- console.debug()
- console.warn()

Error tracing

When execution of a file fails, JSEval displays an error trace, so you can clearly see where the error comes from.

JSEval tool window

Every expression that is evaluated and presented can be further inspected in the dedicated JSEval tool window. Here you can also inspect the deeply nested elements of objects and arrays and copy the values from the tree. Double-clicking an item leads to the point where it is evaluated from.

Tracking time passed

Use the //. comment to track how long it took to reach a specific expression from the execution start.

Support for imports

You can also track files with imports from packages or other project files. Values are updated on changes in the imported files.

Configuring the context of executions

Choose a runtime for executions

When executing your code, you can switch between various Node.js runtime versions to explore differences between them.

Configure TypeScript handling

For TypeScript files, you can also configure TypeScript transpilation handling for Node.js.

From the drop-down list on the toolbar of the JSEval tool window, select one of the following options:

NONE - with this option selected, no TypeScript handling is added. You can still configure custom handling through advanced file settings as described above.
TRANSFORMTYPES - select this option to have --experimental-transform-types appended to the Node.js parameters. Transformation is applied to TypeScript-only types, such as, enum and namespace.
With Node.js 26.0.0 and later, this tag is no longer available.
BUNDLEDTSX - with this option selected, TSX is used to build the file before evaluation.

Configure additional execution properties

You can additionally specify the parameters to be passed to the runtime or to the application, the working directory to run the application in, as well as the environment variables.

Specify advanced evaluation control settings

In the JSEval tool window, click .
In the Advanced File Evaluation Control dialog that opens specify the additional configuration settings

11 May 2026