[feature] Ability to know if variable is declared about ast-grep HOT 3 CLOSED

You can use relational rule https://ast-grep.github.io/guide/rule-config/relational-rule.html

follows and precedes can be used to find if a variable declaration exists.

That said, it is impossible to detect arbitrary variable declarations using YAML. Say, your use case here is finding a fresh identifier that is not defined in the scope. But you can detect if the specific identifier root is defined.

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It should be something like this?

pattern: render($JSX, $ELEMENT);
follows:
  pattern: $BINDING;

Could you please tell me how should I determine if variable is declared? Should I write all ways of declaration: var/const/let/import/function argument, or there is a keyword for this?

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@coderaiser play around the playground is recommended. https://ast-grep.github.io/playground.html

You can also ask questions on https://stackoverflow.com/questions/tagged/ast-grep

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