find-entry-points
Install
$ npm i find-entry-points
Huh?
Example 1
Given a sync or async iterable of paths to the JavaScript files with the
following dependencies between them (a directed arrow from a.js
to b.js
means a.js
imports b.js
):
The findEntryPoints
function would return [['a.js']]
because a.js
is the
entry point of the above JavaScript library or application (it is not imported
by any JavaScript file). The findSingleEntryPoints
function would return
['a.js']
.
Example 2
Given a sync or async iterable of paths to the JavaScript files with the following dependencies between them:
The findEntryPoints
function would return [['a.js'], ['f.js'], ['g.js']]
(order not guaranteed) because a.js
, f.js
, and g.js
are all not imported
by any JavaScript file. Notice that it is possible to have a disconnected
dependency graph. The findSingleEntryPoints
function would return
['a.js', 'f.js', 'g.js']
(order not guaranteed).
Example 3
Given a sync or async iterable of paths to the JavaScript files with the following dependencies between them:
The findEntryPoints
function would return [['a.js'], ['g.js']]
(order not
guaranteed). Notice that cycles are possible because imports are cached. The
findSingleEntryPoints
function would return ['a.js', 'g.js']
(order not
guaranteed).
Example 4
Given a sync or async iterable of paths to the JavaScript files with the following dependencies between them:
The findEntryPoints
function would return
[['a.js'], ['g.js', 'h.js', 'i.js']]
(order not guaranteed). Notice that this
is the first example where an inner array contains more than one element. This
is because g.js
, h.js
, and i.js
are all valid entry points for their graph
component. The findSingleEntryPoints
function would return ['a.js']
(order
not guaranteed).
Usage
Suppose the JavaScript files with the following dependencies between them are
all in a src
directory and that h.js
imports i.js
via a dynamic import:
import { findEntryPoints, findSingleEntryPoints } from 'find-entry-points'
import globby from 'globby'
import * as swc from '@swc/core'
// `globby.stream` returns an async iterable of file paths
console.log(await findEntryPoints(globby.stream('src/**/*.js')))
//=> [['src/a.js'], ['src/g.js', 'src/h.js', 'src/i.js']]
// `findSingleEntryPoints` ignores cyclic entry points
console.log(await findSingleEntryPoints(globby.stream('src/**/*.js')))
// => ['src/a.js']
console.log(
await findEntryPoints(globby.stream('src/**/*.js'), {
followDynamicImports: false
})
)
//=> [['src/a.js'], ['src/i.js']]
console.log(
await findSingleEntryPoints(globby.stream('src/**/*.js'), {
followDynamicImports: false
})
)
// => ['src/a.js', 'src/i.js']
// Use the `transform` option to transform non-standard syntax
// like JSX to standard ECMAScript so that imports can be parsed
console.log(
await findEntryPoints(globby.stream('src/**/*.js'), {
transform: async ({ path, code }) =>
(
await transform(code, {
filename: path,
jsc: { parser: { jsx: true } }
})
).code
})
)
//=> [['src/a.js'], ['src/g.js', 'src/h.js', 'src/i.js']]
console.log(
await findSingleEntryPoints(globby.stream('src/**/*.js'), {
transform: async ({ path, code }) =>
(
await transform(code, {
filename: path,
jsc: { parser: { jsx: true } }
})
).code
})
)
//=> ['src/a.js']
// Use the `parseImports` option to parse imports yourself
console.log(
await findEntryPoints(globby.stream('src/**/*.js'), {
parseImports: async ({ followDynamicImports, file }) => {
const { path, read } = file
// Read the file if you want
const code = await read()
const importedFilenames = yourFancyImportParser(code)
return importedFilenames
}
})
)
See the commented type definitions for clarification.
How?
The package uses
parse-imports
(another
package of mine) to construct a dependency graph, which is a
directed graph,
from the given set of JavaScript files. Then the package finds the
strongly connected components
of the dependency graph using
Tarjan's strongly connected components algorithm,
and constructs a
directed acyclic graph from the strongly connected components.
Finally, the package returns the strongly connected components corresponding to
the vertices with
in-degree
1 in the new directed acyclic graph.
Contributing
Stars are always welcome!
For bugs and feature requests, please create an issue.
For pull requests, please read the contributing guidelines.
License
This is not an official Google product.