defiler/API.md

The API consists of two classes, File and Defiler.

A File represents a physical file on the disk, or a generated virtual file with no particular corresponding file in the filesystem, or a partially or fully transformed physical or virtual/generated file.

A Defiler represents a set of watched files on the disk, plus a set of generated files, plus a set of transforms to execute on them.

File

Constructor

new File(path)

A new File instance to serve as the representation of a physical file, a generated file, or a transformed file. path is the relative path to the file, from some understood root.

Properties

path

The file's path can be retrieved or updated by getting and setting path.

ext

The file's extension (including the preceding .) can be retrieved or updated by getting and setting path. The ext and path properties are kept in sync.

bytes

The file's contents can be updated by getting or setting bytes, which is a Buffer.

text

The file's contents can also be updated by getting of setting text, which is a string. Mutating the bytes Buffer will not be reflected in text, but reassigning the entire bytes or text properties will keep the other in sync.

Defiler

Constructor

new Defiler()

A new Defiler instance to represent a collection of watched physical files and generated files, and transforms to run on them.

Properties

ready

A Promise that's resolved once we've completed the initial wave of processing. This remains unchanged as later watches or changes are triggered.

origFiles

A map of (original) relative paths to File instances for the original physical files.

files

A map of original relative paths to File instances for the transformed files.

origPaths

A sorted array of the relative paths of all of the physical files. This can be used whether or not we've completed the initial wave of processing.

Configuration

add({ gaze, rootPath, read = true })

Register a Gaze instance.

• gaze - the Gaze instance
• rootPath - the path that all of our paths should be relative to
• read - whether to actually read in the contents of the files for this Gaze. If false, the files will still be run through all of the transforms, but they will have null bytes and text

Returns the Defiler instance for chaining.

add({ transform, if })

Register a new transform to be applied to all files.

• transform(file) - a transformer function, which is passed a File instance to mutate. In your function, this will be the current Defiler instance. The function can return a Promise to indicate when it's done
• if(file) - (optional) a function that, if present, will be called with the File instance before calling the main transform. In your function, this will be the current Defiler instance. If the function returns false or a Promise resolving to false, the transform is skipped

Returns the Defiler instance for chaining.

add({ path, generator })

Register a new generated file, not directly sourced from a physical file.

• path - the relative path of the file to register the generator for
• generator(file) - a function that is passed a new File instance containing only a path, which it should then mutate. In your function, this will be the current Defiler instance. The function can return a Promise to indicate when it's done

Returns the Defiler instance for chaining.

Execution

exec()

Starts the Defiler running. No additional configuration (registering Gazes, transforms, or generated files) can happen after this.

Operation

use(path, { from })

Waits for a file or array of files to be ready.

• path - The path, or array of paths, to wait for to become available.
• from - (optional) A path of a file to re-process if any of the file or files given in path change. (Typically, this is the path to the file you are currently transforming or generating.)

Returns a Promise resolving to the File instance or an array of File instances.

This can be asked for physical or generated files. If you ask for one or more physical files during the initial wave of processing before everything has been read in and processed, it will wait for the file or files to be ready (and transformed). Asking for something that is neither a known physical file nor a registered generated file will not throw an error, but will instead simple return undefined.

If a path from is passed, from is registered as depending on the file or files in path. When the file or files in path change, the file at from will be automatically re-transformed (using refile, below). If you're calling use inside a transform or generator, from is typically going to be the path of the file you're transforming or generating.

refile(path)

Manually re-transform a File. This can be from a physical file or a generated one. Returns a Promise to indicate when all processing is complete. Re-transforming a physical file will use the version of it that was last read into memory. Re-transforming a generated file will call its generator again.

Returns a Promise to indicate when all processing is complete.

Typically, you would not need to call this directly, as it would be automatically handled by the dependencies registered by use.

addFile(file)

Manually insert a non-physical File, running it through all the transforms.

Returns a Promise to indicate when all processing is complete.

close()

Close all of the attached Gazes.

Events

Defiler extends Node's EventEmitter, and emits four kinds of events.

origFile(origPath, file)

An origFile event is emitted when the original version of a physical file has been read in. It's emitted with two arguments: the file's original relative path and the File instance.

file(origPath, file)

A file event is emitted after all transforms on a file are complete. It's emitted with two arguments: the file's original relative path and the fully transformed File instance.

deleted(origPath)

A deleted event is emitted when a watched physical file has been deleted. It's emitted with one argument: the (original) relative path to the file.

error(origPath, file, err)

An error event is emitted if a file transform or a file generator throws an exception or returns a Promise that rejects. It's emitted with three arguments: the file's original relative path, the File instance that caused the error, and the thrown error.