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Apply Code Action

The apply-code-action command exposes LSP code actions via the CLI, allowing you to apply autofixes and code transformations without an editor. This is useful for scripting, CI pipelines, or batch-fixing files from the command line.

Usage​

flow apply-code-action SUBCOMMAND [OPTIONS]... FILE

The command requires a running Flow server. If one is not already running, it will be started automatically.

Subcommands​

experimental.quickfix​

Applies all safe quickfixes to a file. These are the same quickfixes that your editor shows via LSP code actions, such as adding suppression comments or replacing deprecated syntax.

flow apply-code-action 'experimental.quickfix' [OPTIONS] FILE

By default, only safe quickfixes are applied. You can optionally include one additional best-effort fix using the --include-best-effort-fix flag. Best-effort fixes may change the runtime semantics of your program (for example, adding a type annotation to a variable declaration to satisfy a type error).

Options:

  • --in-place: Overwrite the input file with the result. Without this flag, the transformed file contents are printed to stdout.
  • --include-best-effort-fix: Include one additional best-effort quickfix beyond the safe fixes.

Example:

# Print the file with all safe quickfixes applied
flow apply-code-action 'experimental.quickfix' src/app.js

# Apply safe quickfixes and overwrite the file
flow apply-code-action 'experimental.quickfix' --in-place src/app.js

# Also apply one best-effort fix
flow apply-code-action 'experimental.quickfix' --include-best-effort-fix src/app.js

source.addMissingImports​

Adds missing import statements for unresolved references in a file. Flow resolves each unbound name to an export in your project and inserts the appropriate import statement.

flow apply-code-action 'source.addMissingImports' [OPTIONS] FILE

Options:

  • --in-place: Overwrite the input file with the result. Without this flag, the transformed file contents are printed to stdout.

Example:

Given a file app.js that references OtherModule without importing it:

// @flow

OtherModule;

Running the command:

flow apply-code-action 'source.addMissingImports' app.js

produces output with the import added:

// @flow

import OtherModule from "./OtherModule";

OtherModule;

To update the file in place:

flow apply-code-action 'source.addMissingImports' --in-place app.js

suggestImports​

Lists import suggestions for all unbound names in a file, ranked by usage. Unlike the other subcommands, this does not modify the file. Instead, it outputs a JSON object describing the available import code actions for each unresolved name.

flow apply-code-action suggestImports [OPTIONS] FILE

Options:

  • --json: Output results in JSON format (default behavior for this subcommand).
  • --pretty: Pretty-print the JSON output.

Example:

flow apply-code-action suggestImports --pretty src/app.js

The output is a JSON object keyed by unbound name, where each value is an array of possible import actions:

{
  "OtherModule": [
    {
      "title": "Import default from ./OtherModule",
      "kind": "quickfix",
      "edit": {
        "changes": {
          "file:///path/to/app.js": [
            {
              "newText": "import OtherModule from \"./OtherModule\";\n\n",
              "range": {
                "start": { "character": 0, "line": 1 },
                "end": { "character": 0, "line": 1 }
              }
            }
          ]
        }
      }
    }
  ]
}

When multiple modules export the same name, all candidates are listed so you can choose the appropriate one.