tldr/pages/common/sg.md

sg

Ast-grep is a tool for code structural search, lint, and rewriting. More information: https://ast-grep.github.io/guide/introduction.html.

• Scan for possible queries using interactive mode:

sg scan --interactive

• Rewrite code in the current directory using patterns:

sg run --pattern '{{foo}}' --rewrite '{{bar}}' --lang {{python}}

• Visualize possible changes without applying them:

sg run --pattern '{{useState<number>($A)}}' --rewrite '{{useState($A)}}' --lang {{typescript}}

• Output results as JSON, extract information using jq and interactively view it using jless:

sg run --pattern '{{Some($A)}}' --rewrite '{{None}}' --json | jq '{{.[].replacement}}' | jless