astx
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Super powerful structural search and replace for JavaScript and TypeScript to automate your refactoring
constructor(backend: Backend, paths: NodePath<any>[] | Match[], options?: { withCaptures?: Match[] }).find(...) (Astx).closest(...) (Astx)FindOptions
.find(...).replace(...) (void).size() (number)[name: `$${string}` | `$$${string}` | `$$$${string}`] (Astx).placeholder (string | undefined).node (Node).path (NodePath).code (string).stringValue (string)[Symbol.iterator] (Iterator<Astx>).matches (Match[]).match (Match).paths (NodePath[]).nodes (Node[]).filter(iteratee) (Astx).map<T>(iteratee) (T[]).at(index) (Astx).withCaptures(...captures) (Astx)Simple refactors can be tedious and repetitive. For example say you want to make the following change across a codebase:
// before:
rmdir('old/stuff')
rmdir('new/stuff', true)
// after:
rmdir('old/stuff')
rmdir('new/stuff', { force: true })
Changing a bunch of calls to rmdir by hand would suck. You could try using regex replace, but it's fiddly and wouldn't tolerate whitespace and
linebreaks well unless you work really hard at the regex. You could even use jscodeshift, but it takes too long for simple cases like this, and starts to feel harder than necessary...
Now there's a better option...you can refactor with confidence using astx!
astx \
--find 'rmdir($path, $force)' \
--replace 'rmdir($path, { force: $force })'
This is a basic example of astx patterns, which are just JS or TS code that can contain placeholders and other special matching constructs; astx looks for
code matching the pattern, accepting any expression in place of $path and $force. Then astx replaces
each match with the replace pattern, substituting the expressions it captured for $path ('new/stuff') and $force (true).
But this is just the beginning; astx patterns can be much more complex and powerful than this, and for really advanced use cases it has
an intuitive API you can use:
for (const match of astx.find`rmdir($path, $force)`()) {
const { $path, $force } = match
// do stuff with $path.node, $path.code, etc...
}
Got a lot of Do not access Object.prototype method 'hasOwnProperty' from target object errors?
// astx.js
exports.find = `$a.hasOwnProperty($b)`
exports.replace = `Object.hasOwn($a, $b)`
Recently for work I wanted to make this change:
// before
const pkg = OrgPackage({
subPackage: [
'services',
async ? 'async' : 'blocking',
...namespace,
Names.ServiceType({ resource, async }),
],
})
// after
const pkg = [
...OrgPackage(),
'services',
async ? 'async' : 'blocking',
...namespace,
Names.ServiceType({ resource, async }),
]
This is simple to do with list matching:
// astx.js
exports.find = `OrgPackage({subPackage: [$$p]})`
exports.replace = `[...OrgPackage(), $$p]`
// astx.js
exports.find = `const $id = require('$source')`
exports.replace = `import $id from '$source'`
// astx.js
export const find = `if ($a) { if ($b) $body }`
export const replace = `if ($a && $b) $body`
In jscodeshift-add-imports I had a bunch of test cases following this pattern:
it(`leaves existing default imports untouched`, function () {
const code = `import Baz from 'baz'`
const root = j(code)
const result = addImports(root, statement`import Foo from 'baz'`)
expect(result).to.deep.equal({ Foo: 'Baz' })
expect(root.toSource()).to.equal(code)
})
I wanted to make them more DRY, like this:
it(`leaves existing default imports untouched`, function () {
testCase({
code: `import Baz from 'baz'`,
add: `import Foo from 'baz'`,
expectedCode: `import Baz from 'baz'`,
expectedReturn: { Foo: 'Baz' },
})
})
Here was a transform for the above. (Of course, I had to run a few variations of this for cases where the expected code was different, etc.)
exports.find = `
const code = $code
const root = j(code)
const result = addImports(root, statement\`$add\`)
expect(result).to.deep.equal($expectedReturn)
expect(root.toSource()).to.equal(code)
`
exports.replace = `
testCase({
code: $code,
add: \`$add\`,
expectedCode: $code,
expectedReturn: $expectedReturn,
})
`
I just finally got version 2 released as of December 2022 after tons of hard work 🎉
Right now I'm working on the VSCode Extension.
After that I want to make a documentation website that better illustrates how to use astx.
The VSCode Extension is currently in beta, but try it out!
While I was thinking about making this I discovered grasp, a similar tool that inspired the $ capture syntax.
There are several reasons I decided to make astx anyway:
grasp -e 'setValue($k, $v, true)' -R 'setValueSilently({{k}}, {{v}})' file.jsjscodeshift-like API I could use in JS for advanced use cases that are probably awkward/impossible in GraspSo the philosophy of astx is:
Paste your code into AST Explorer if you need to learn about the structure of the AST.
Astx find patterns are just JavaScript or TypeScript code that may contain placeholder wildcards or other special constructs
like $Or(A, B). Generally speaking, parts of the pattern that aren't wildcards or special constructs have to match exactly.
For example, the find pattern foo($a) matches any call to the function foo with a single argument. The argument can anything
and is captured as $a.
Replace patterns are almost identical to find patterns, except that placeholders get replaced with whatever was captured into
the placeholder name by the find pattern, and special find constructs like $Or(A, B) have no special meaning in replace patterns.
(In the future, there may be special replace constructs that perform some kind of transformation on captured nodes.)
For example, the find pattern foo($a) matches foo(1 + 2), then the replace pattern foo({ value: $a }) will generate the code
foo({ value: 1 + 2 }).
Generally speaking, an identifier starting with $ is a placeholder that functions like a wildcard. There are three types of placeholders:
$<name> matches any single node ("node placeholder")$$<name> matches a contiguous list of nodes ("array placeholder")$$$<name>: matches all other siblings ("rest placeholder")The <name> (if given) must start with a letter or number; otherwise the identifier will
not be treated as a placeholder.
Rest placeholders ($$$) may not be sibilings of ordered list placeholders ($$).
Unless a placeholder is anonymous, it will "capture" the matched node(s), meaning you can use the same placeholder in the replacement pattern to interpolate the matched node(s) into the generated replacement. In the Node API you can also access the captured AST paths/nodes via the placeholder name.
$<name>)These placeholders match a single node. For example, the pattern [$a, $b] matches an array expression with two elements,
and those elements are captured as $a and $b.
$$<name>)These placeholders match a contiguous list of nodes. For example, the pattern [1, $$a, 2, $$b] matches an array expression
with 1 as the first element, and 2 as a succeeding element. Any elements between 1 and the first 2 is captured as $$a,
and elements after the first 2 are captured as $$b.
$$$<name>)These placeholders match the rest of the siblings that weren't matched by something else. For example, the pattern [1, $$$a, 2]
matches an array expression that has elements 1 and 2 at any index. Any other elements (including additional occurrences of 1
and 2) are captured as $$$a.
You can use a placeholder without a name to match node(s) without capturing them. $ will match any single node, $$ will match a
contiguous list of nodes, and $$$ will match all other siblings.
If you use the same capture placeholder more than once, subsequent positions will have to match what was captured for the first occurrence of the placeholder.
For example, the pattern foo($a, $a, $b, $b) will match only foo(1, 1, {foo: 1}, {foo: 1}) in the following:
foo(1, 1, { foo: 1 }, { foo: 1 }) // match
foo(1, 2, { foo: 1 }, { foo: 1 }) // no match
foo(1, 1, { foo: 1 }, { bar: 1 }) // no match
Note: array capture placeholders ($$a) and rest capture placeholders ($$$a) don't currently support backreferencing.
An ObjectExpression (aka object literal) pattern will match any ObjectExpression in your code with the same properties in any order.
It will not match if there are missing or additional properties. For example, { foo: 1, bar: $bar } will match { foo: 1, bar: 2 } or { bar: 'hello', foo: 1 }
but not { foo: 1 } or { foo: 1, bar: 2, baz: 3 }.
You can match additional properties by using ...$$captureName, for example { foo: 1, ...$$rest } will match { foo: 1 }, { foo: 1, bar: 2 }, { foo: 1, bar: 2, ...props } etc.
The additional properties will be captured in match.arrayCaptures/match.arrayPathCaptures, and can be spread in replacement expressions. For example,
astx.find`{ foo: 1, ...$$rest }`.replace`{ bar: 1, ...$$rest }` will transform { foo: 1, qux: {}, ...props } into { bar: 1, qux: {}, ...props }.
A spread property that isn't of the form /^\$\$[a-z0-9]+$/i is not a capture placeholder, for example { ...foo } will only match { ...foo } and { ...$_$foo } will only
match { ...$$foo } (leading $_ is an escape for $).
There is currently no way to match properties in a specific order, but it could be added in the future.
In many cases where there is a list of nodes in the AST you can match
multiple elements with a placeholder starting with $$. For example, [$$before, 3, $$after] will match any array expression containing an element 3; elements before the
first 3 will be captured in $$before and elements after the first 3 will be captured in $$after.
This works even with block statements. For example, function foo() { $$before; throw new Error('test'); $$after; } will match function foo() that contains a throw new Error('test'),
and the statements before and after that throw statement will get captured in $$before and $$after, respectively.
In some cases list matching will be ordered by default, and in some cases it will be unordered. For example, ObjectExpression property matches are unordered by default, as shown in the table below.
Using a $$ placeholder or the special $Ordered placeholder will force ordered matching. Using a $$$ placeholder or the special $Unordered placeholder will force unordered matching.
If you use a placeholder starting with $$$, it's treated as a "rest" capture, and all other elements of the
match expression will be matched out of order. For example, import {a, b, $$$rest} from 'foo' would match
import {c, b, d, e, a} from 'foo', putting specifiers c, d, and e, into the $$$rest placeholder.
Rest placeholders ($$$) may not be sibilings of ordered list placeholders ($$).
Some items marked TODO probably actually work, but are untested.
| Type | Supports list matching? | Unordered by default? | Notes |
|---|---|---|---|
ArrayExpression.elements | ✅ | ||
ArrayPattern.elements | ✅ | ||
BlockStatement.body | ✅ | ||
CallExpression.arguments | ✅ | ||
Class(Declaration/Expression).implements | ✅ | ✅ | |
ClassBody.body | ✅ | ✅ | |
ComprehensionExpression.blocks | TODO | ||
DeclareClass.body | TODO | ✅ | |
DeclareClass.implements | TODO | ✅ | |
DeclareExportDeclaration.specifiers | TODO | ✅ | |
DeclareInterface.body | TODO | ||
DeclareInterface.extends | TODO | ||
DoExpression.body | TODO | ||
ExportNamedDeclaration.specifiers | ✅ | ✅ | |
Function.decorators | TODO | ||
Function.params | ✅ | ||
FunctionTypeAnnotation/TSFunctionType.params | ✅ | ||
GeneratorExpression.blocks | TODO | ||
ImportDeclaration.specifiers | ✅ | ✅ | |
(TS)InterfaceDeclaration.body | TODO | ✅ | |
(TS)InterfaceDeclaration.extends | TODO | ✅ | |
IntersectionTypeAnnotation/TSIntersectionType.types | ✅ | ✅ | |
JSX(Element/Fragment).children | ✅ | ||
JSX(Opening)Element.attributes | ✅ | ✅ | |
MethodDefinition.decorators | TODO | ||
NewExpression.arguments | ✅ | ||
ObjectExpression.properties | ✅ | ✅ | |
ObjectPattern.decorators | TODO | ||
ObjectPattern.properties | ✅ | ✅ | |
(ObjectTypeAnnotation/TSTypeLiteral).properties | ✅ | ✅ | Use $a: $ to match one property, $$a: $ or $$$a: $ to match multiple |
Program.body | ✅ | ||
Property.decorators | TODO | ||
SequenceExpression | ✅ | ||
SwitchCase.consequent | ✅ | ||
SwitchStatement.cases | TODO | ||
TemplateLiteral.quasis/expressions | ❓ not sure if I can come up with a syntax | ||
TryStatement.guardedHandlers | TODO | ||
TryStatement.handlers | TODO | ||
TSFunctionType.parameters | ✅ | ||
TSCallSignatureDeclaration.parameters | TODO | ||
TSConstructorType.parameters | TODO | ||
TSConstructSignatureDeclaration.parameters | TODO | ||
TSDeclareFunction.params | TODO | ||
TSDeclareMethod.params | TODO | ||
EnumDeclaration.body/TSEnumDeclaration.members | TODO | ✅ | |
TSIndexSignature.parameters | TODO | ||
TSMethodSignature.parameters | TODO | ||
TSModuleBlock.body | TODO | ||
TSTypeLiteral.members | ✅ | ✅ | |
TupleTypeAnnotation/TSTupleType.types | ✅ | ||
(TS)TypeParameterDeclaration.params | ✅ | ||
(TS)TypeParameterInstantiation.params | ✅ | ||
UnionTypeAnnotation/TSUnionType.types | ✅ | ✅ | |
VariableDeclaration.declarations | ✅ | ||
WithStatement.body | ❌ who uses with statements... |
A string that's just a placeholder like '$foo' will match any string and capture its contents into match.stringCaptures.$foo.
The same escaping rules apply as for identifiers. This also works for template literals like `$foo` and tagged template literals like doSomething`$foo`.
This can be helpful for working with import statements. For example, see Converting require statements to imports.
An empty comment (/**/) in a pattern will "extract" a node for matching.
For example the pattern const x = { /**/ $key: $value } will just
match ObjectProperty nodes against $key: $value.
The parser wouldn't be able to parse $key: $value by itself or
know that you mean an ObjectProperty, as opposed to something different like the x: number in const x: number = 1, so using /**/ enables you to work around this. You can use this to match any node type that isn't a valid expression or statement by itself. For example type T = /**/ Array<number>
would match Array<number> type annotations.
/**/ also works in replacement patterns.
$Maybe(pattern)Matches either the given expression or no node in its place. For example let $a = $Maybe(2) will match let foo = 2 and let foo (with no initializer), but not let foo = 3.
$Or(...)Matches nodes that match at least one of the given patterns. For example $Or(foo($$args), {a: $value}) will match calls to foo and object literals with only an a property.
$And(...)Matches nodes that match all of the given patterns. This is mostly useful for narrowing down the types of nodes that can be captured into a given placeholder. For example, let $a = $And($init, $a + $b) will match let declarations where the initializer matches $a + $b, and capture the initializer as $init.
$Maybe<pattern>Matches either the given type annotation or no node in its place. For example let $a: $Maybe<number> will match let foo: number and let foo (with no type annotation), but not let foo: string``let foo: string.
$Or<...>Matches nodes that match at least one of the given type annotations. For example let $x: $Or<number[], string[]> will match let declarations of type number[] or string[].
$And<...>Matches nodes that match all of the given type annotations. This is mostly useful for narrowing down the types of nodes that can be captured into a given placeholder. For example, let $a: $And<$type, $elem[]> will match let declarations where the type annotation matches $elem[], and capture the type annotation as $type.
$OrderedForces the pattern to match sibling nodes in the same order.
$UnorderedForces the pattern to match sibling nodes in any order.
import { NodePath } from 'astx'
This is the same NodePath interface as ast-types, with some improvements to the method type definitions.
astx uses ast-types to traverse code, in hopes of supporting different parsers in the future.
import { Astx } from 'astx'
constructor(backend: Backend, paths: NodePath<any>[] | Match[], options?: { withCaptures?: Match[] })backend is the parser/generator implementation being used.
paths specifies the NodePaths or Matches you want Astx methods
to search/operate on.
.find(...) (Astx)Finds matches for the given pattern within this instance's starting paths and returns an Astx instance containing the matches.
If you call astx.find('foo($$args)') on the initial instance passed to your transform function, it will find all calls to foo within the file, and return those matches in a new Astx instance.
Methods on the returned instance will operate only on the matched paths.
For example if you do astx.find('foo($$args)').find('$a + $b'), the second find call will only search for $a + $b within matches to foo($$args), rather than anywhere in the file.
You can call .find as a method or tagged template literal:
.find`pattern`(options?: FindOptions).find(pattern: string | string[] | Node | Node[] | NodePath | NodePath[], options?: FindOptions)If you give the pattern as a string, it must be a valid expression or statement(s). Otherwise it should be valid
AST node(s) you already parsed or constructed.
You can interpolate strings, AST nodes, arrays of AST nodes, and Astx instances in the tagged template literal.
For example you could do astx.find`${t.identifier('foo')} + 3`().
Or you could match multiple statements by doing
astx.findStatements`
const $a = $b;
$$c;
const $d = $a + $e;
`()
This would match (for example) the statements const foo = 1; const bar = foo + 5;, with any number of statements between them.
.closest(...) (Astx)Like .find(), but searches up the AST ancestors instead of down into descendants; finds the closest enclosing node of each input path that matches the given pattern.
FindOptionsAn object with the following optional properties:
FindOptions.where ({ [captureName: string]: (path: Astx) => boolean })Where conditions for node captures. For example if your find pattern is $a(), you could have
{ where: { $a: astx => /foo|bar/.test(astx.node.name) } }, which would only match zero-argument calls
to foo or bar.
.find(...).replace(...) (void)Finds and replaces matches for the given pattern within root.
There are several different ways you can call .replace. You can call .find in any way described above.
.find(...).replace`replacement`().find(...).replace(replacement: string | string | Node | Node[]).find(...).replace(replacement: (match: Astx, parse: ParsePattern) => string).find(...).replace(replacement: (match: Astx, parse: ParsePattern) => Node | Node[])If you give the replacement as a string, it must be a valid expression or statement.
You can give the replacement as AST node(s) you already parsed or constructed.
Or you can give a replacement function, which will be called with each match and must return a string or Node | Node[] (you can use the parse tagged template string function provided as the second argument to parse code into a string.
For example, you could uppercase the function names in all zero-argument function calls (foo(); bar() becomes FOO(); BAR()) with this:
astx
.find`$fn()`
.replace(({ captures: { $fn } }) => `${$fn.name.toUpperCase()}()`)
.size() (number)Returns the number of matches from the .find() or .closest() call that returned this instance.
[name: `$${string}` | `$$${string}` | `$$$${string}`] (Astx)Gets an Astx instance focused on the capture(s) with the given name.
For example, you can do:
for (const { $v } of astx.find`process.env.$v`()) {
report($v.code)
}
.placeholder (string | undefined)The name of the placeholder this instance represents. For example:
const match = astx.find`function $fn($$params) { $$body }`()
console.log(match.placeholder) // undefined
const { $fn, $$params } = match
console.log($fn.placeholder) // $fn
console.log($$params.placeholder) // $$params
.node (Node)Returns the first node of the first match. Throws an error if there are no matches.
.path (NodePath)Returns the first path of the first match. Throws an error if there are no matches.
.code (string)Generates code from the first node of the first match. Throws an error if there are no matches.
.stringValue (string)Returns the string value of the first node if the focused capture is a string capture. Throws an error if there are no matches.
[Symbol.iterator] (Iterator<Astx>)Iterates through each match, returning an Astx instance for each match.
.matches (Match[])Gets the matches from the .find() or .closest() call that returned this instance.
.match (Match)Gets the first match from the .find() or .closest() call that returned this instance.
Throws an error if there were no matches.
.paths (NodePath[])Returns the paths that .find() and .closest() will search within.
If this instance was returned by .find() or .closest(), these are
the paths of nodes that matched the search pattern.
.nodes (Node[])Returns the nodes that .find() and .closest() will search within.
If this instance was returned by .find() or .closest(), these are
the nodes that matched the search pattern.
.filter(iteratee) (Astx)Filters the matches.
iteratee is function that will be called with match: Astx, index: number, parent: Astx and returns true or false. Only matches for which iteratee returns true will be included in the result.
.map<T>(iteratee) (T[])Maps the matches.
iteratee is function that will be called with match: Astx, index: number, parent: Astx and returns the value to include
in the result array.
.at(index) (Astx)Selects the match at the given index.
.withCaptures(...captures) (Astx)Returns an Astx instance that contains captures from the given ...captures in addition to captures present in this instance.
You can pass the following kinds of arguments:
Astx instances - all captures from the instance will be included.Astx[placeholder] instances - capture(s) for the given placeholder will be included.{ $name: Astx[placeholder] } - capture(s) for the given placeholder, renamed to $name.Match objectsimport { type Match } from 'astx'
.typeThe type of match: 'node' or 'nodes'.
.pathThe NodePath of the matched node. If type is 'nodes', this will be paths[0].
.nodeThe matched Node. If type is 'nodes', this will be nodes[0].
.pathsThe NodePaths of the matched nodes.
.nodesThe matched Nodes.
.capturesThe Nodes captured from placeholders in the match pattern. For example if the pattern was foo($bar), .captures.$bar will be the Node of the first argument.
.pathCapturesThe NodePaths captured from placeholders in the match pattern. For example if the pattern was foo($bar), .pathCaptures.$bar will be the NodePath of the first argument.
.arrayCapturesThe Node[]s captured from array placeholders in the match pattern. For example if the pattern was foo({ ...$bar }), .arrayCaptures.$bar will be the Node[]s of the object properties.
.arrayPathCapturesThe NodePath[]s captured from array placeholders in the match pattern. For example if the pattern was foo({ ...$bar }), .pathArrayCaptures.$bar will be the NodePath[]s of the object properties.
.stringCapturesThe string values captured from string placeholders in the match
pattern. For example if the pattern was import foo from '$foo',
stringCaptures.$foo will be the import path.
Like jscodeshift, you can put code to perform a transform in a .ts or .js file (defaults to astx.ts or astx.js in the working directory, unless you specify a different file with the -t CLI option).
The transform file API is a bit different from jscodeshift though. You can have the following exports:
exports.find (optional)A code string or AST node of the pattern to find in the files being transformed.
exports.where (optional)Where conditions for capture placeholders in exports.find.
See FindOptions.where ({ [captureName: string]: (path: NodePath<any>) => boolean }) for more information.
exports.replace (optional)A code string, AST node, or replace function to replace matches of exports.find with.
The function arguments are the same as described in .find().replace() or
.findStatements().replace(), depending on whether exports.find
is multiple statements or not.
exports.astx (optional)A function to perform an arbitrary transform using the Astx API. It gets called with an object with the following properties:
file (string) - The path to the file being transformedsource (string) - The source code of the file being transformedastx (Astx) - the Astx API instancet (AstTypes) - ast-types definitions for the chosen parserexpression - tagged template literal for parsing code as an expressionstatement - tagged template literal for parsing code as a statementstatements - tagged template literal for parsing code as an array of statementsreport ((message: unknown) => void)Unlike jscodeshift, your transform function can be async, and it doesn't have to return the transformed code,
but you can return a string. You can also return null to
skip the file.
exports.onReport (optional)If your call report(x) from an exports.astx function, this will be called with
onReport({ file, report: x }).
If you are using multiple worker threads, onReport
will be called in the parent process, so the report
message must be a serializable value. This allows a
transform to collect reports from all workers (and then
potentially do something with them in finish).
If onReport returns a Promise it will be awaited.
exports.finish (optional)This will be called after the transform has been run on all input files.
If you are using multiple worker threads, finish
will be called in the parent process. You can use
onReport and finish
together to collect information from each input file
and produce some kind of combined output at the end.
If finish returns a Promise it will be awaited.
astx supports configuration in the following places (via cosmiconfig):
astx property in package.json.astxrc file in JSON or YAML format.astxrc.json, .astxrc.yaml, .astxrc.yml, .astxrc.js, or .astxrc.cjs fileastx.config.js or astx.config.cjs CommonJS module exporting an objectIf your codebase is formatted with prettier, I recommend trying this first:
{
"parser": "babel/auto",
"parserOptions": {
"preserveFormat": "generatorHack"
}
}
(or as CLI options)
--parser babel/auto --parserOptions '{"preserveFormat": "generatorHack"}'
If this fails you can try parser: 'recast/babel/auto' or the non-/auto parsers.
Your mileage may vary with recast; they just aren't able to keep it up to date
with new syntax features in JS and TS quickly enough, and I've seen it output invalid
syntax too many times.
From now on I'm going to work on a reliable solution using @babel/generator or prettier
to print the modified AST, with a hook to use the original source verbatim for unmodified
nodes.
parserThe parser to use. Options:
babel/auto (default,)babel (faster than babel/auto, but uses default parse options instead, you may have to configure parserOptions)recast/babelrecast/babel/autobabel/auto automatically determines parse options from your babel config if present.
babel uses fixed parse options instead, so it's faster than babel/auto, but you may have to configure parserOptions.
The recast/babel(/auto) options use recast to preserve formatting.
I've seen recast output invalid syntax on some files, so use with caution.
parserOptionsOptions to pass to the parser. Right now this is just the @babel/parser options plus
the following additional options:
preserveFormat (applies to: babel, babel/auto)
preserveFormat: 'generatorHack' uses an experimental hack
to preserve format of all unchanged nodes by hijacking
internal @babel/generator API.prettierIf false, don't try to use prettier to reformat transformed source code.
Defaults to true.
Astx includes a CLI for performing transforms. The CLI will process the given files, then print out a diff of what will be changed, and prompt you to confirm you want to write the changes.
It will parse with babel by default using the version installed in your project and your project's babel config, if any.
You can pass --parser recast/babel if you want to use recast to try to preserve
formatting in the output, but I sometimes see syntax errors in its output.
Unlike jscodeshift, if prettier is installed in your project, it will format the transformed code with prettier.
Usage:
astx -f <code> [<files...>] [<directories...>]
Searches for the -f pattern in the given files and directories
and prints out the matches in context
astx -f <code> -r <code> [<files...>] [<directories...>]
Quick search and replace in the given files and directories
(make sure to quote code)
Example:
astx -f 'rmdir($path, $force)' -r 'rmdir($path, { force: $force })' src
astx -t <transformFile> [<files ...>] [<directories ...>]
Applies a transform file to the given files and directories
astx [<files ...>] [<directories ...>]
Applies the default transform file (astx.ts or astx.js in working directory)
to the given files and directories
Options:
--help Show help [boolean]
--version Show version number [boolean]
-t, --transform path to the transform file. Can be either a local path or
url. Defaults to ./astx.ts or ./astx.js if --find isn't
given
--parser parser to use (options: babel, babel/auto, recast/babel,
recast/babel/auto) [string]
--parserOptions options for parser [string]
-f, --find search pattern [string]
-r, --replace replace pattern [string]
-y, --yes don't ask for confirmation before writing changes
[boolean]
--gitignore ignore gitignored files [boolean] [default: true]
--workers number of worker threads to use [number]
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super powerful structural search and replace for JavaScript and TypeScript to automate your refactoring
The npm package astx receives a total of 55 weekly downloads. As such, astx popularity was classified as not popular.
We found that astx demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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