orsa-js-analyzer

Orsa Javascript analyzer

There is a reason why languages like TypeScript exist, and that's because Javascript, as much as we love it, has about fifteen ways to do anything. That makes it really hard to pick out language features, like class definitions, imports, exports, JSX uses, etc. This library exists apart from Orsa to make it easier to manage the pattern matching for features in Javascript.

This library normalizes the different ways that a feature is expressed in Javascript into a standard set of feature objects. For example, const Foo = React.createClass({...}), class Foo extends React.Component { ... }, and const MyComponent = (props) => (...); are all normalized into a class with different metadata. This makes it easier for downstream analysis applications, like Orsa, to get a high level view of what is defined and where.

Terminology

Term	Meaning
Features	An important feature in a JS file. This includes things like class definitions, uses of JSX, imports and requires. All features have a type which define what the feature is, as well as a start and end which store the start and end line numbers. Beyond that each feature has different attributes.
Matcher	A function that, given an AST node and a path, returns a feature if it finds one.

Class

Field	Type	Description
start	number	The starting line number.
end	number	The ending line number.
type	string	class
name	string	The name of the class.
superClass	string	The superclass
metadata	object	Additional metadata about the class.
metadata.react	boolean	True if this is a react component.
metadata.stateless	boolean	True if this is a stateless react component.
methods	array	An array of methods
jsDoc	object	JSDoc information

Method

Field	Type	Description
start	number	The starting line number.
end	number	The ending line number.
type	string	method
name	string	The name of the method.
kind	string	The kind of the method as defined by babylon.
params	array	The parameters.
jsDoc	object	JSDoc information

Parameter

Field	Type	Description
start	number	The starting line number.
end	number	The ending line number.
type	string	parameter
name	string	The name of the method.

Import

Field	Type	Description
start	number	The starting line number.
end	number	The ending line number.
type	string	import
from	string	The name of what's being imported.
keys	array	The names of the variables that the import is being assigned to.

JSX Usage

Field	Type	Description
start	number	The starting line number.
end	number	The ending line number.
type	string	jsx-usage
name	string	The name of the component.
base	string	The base name of the component if it's in the form of <Foo.Bar /> base would be Foo.
attributes	array	The attributes used by the component invocation.

Connection to orsa-ast-parser

There is a development dependency on orsa-ast-parser because we want't to ensure that the AST that we are traversing is based on the same babylon parameters as is used by Orsa core.