Language Server

Important project files

• language-configuration.json - the language configuration used in monaco editors, defining the tokens that are used for comments and brackets.
• src/grammar/ - a folder containing the grammar definition of the language.
• langium-config.json - the configuration for the Langium generator.

FAQ

Why is the linting rule @typescript-eslint/no-unnecessary-condition sometimes disabled?

The rule is disabled in places, where we work with potentially incomplete AST nodes.

Langium generates separate interfaces for each kind of AST node. According to the generated interfaces, their properties are never undefined but in reality they might be.

So, in order to write safe code, we need to handle those cases where properties may be undefined and thus use conditions for checking the actual value against undefined. ESLint considers such conditions unnecessary (due to the interfaces), which is the reason for disabling that particular rule.