jscodeshift

What jscodeshift is

jscodeshift is a toolkit for creating and running codemods across JavaScript and TypeScript files. A codemod parses code into an abstract syntax tree, changes selected nodes, and turns the result back into source code. The runner applies a transform file by file and reports how many files were unchanged. From the command line, you can supply a local transform, a transform URL, or file paths through standard input. Parser choices include Babel, Babylon, Flow, TypeScript, and TSX, with Babel as the default. The CLI can limit child processes, select file extensions, and exclude files with ignore patterns or configuration files. Dry-run mode previews a transformation without changing files. Its API supports traversing, filtering, finding, replacing, inserting, removing, and renaming syntax-tree nodes, with optional formatting when generating output. jscodeshift wraps recast, which aims to retain the original code style. It also includes Jest and Jasmine utilities for fixture-based or inline transform tests. The toolkit is free and available for Linux, macOS, Windows, and self-hosted environments.