Template Pig

Create and use simple to complex file/folder templates leveraging JavaScript template literals.

Features

Animated GIF and description coming "soon."

Create a template

Let’s walk through making a very simple single-file template.

• In the {root} folder of your VS Code workspace, create a folder named .templates.
• Create a subfolder named whatever you like. For example, Documentation.
• Create a file named .pig.js in your subfolder.
• Create a file named Document.md in your subfolder.
• Paste this into {root}/.templates/Documentation/.pig.js:

// Metadata used when picking a template.
pig.name = 'Markdown document'
pig.description = '(.md)'
pig.detail = 'Add documentation to this project.'

// Executed when this user is selected by the user, or if the
// .templates folder only has a single template.
pig.executeAsync = async () => {
  // Use VS Code API to prompt user about how they’d like to customize this template instance.
  const title = await showInputBox({ 
    title: 'What are you documenting?', 
    placeHolder: 'Title', 
    prompt: 'Should be singular'
  })
  if (!title) return // Returning a falsy value (undefined here) aborts template instantiation.

  const sectionOptions = [ prepicked('Features'), prepicked('Settings'), prepicked('Known issues') ]
  const selectedSections = await showQuickPick(baseClassOptions, { title: 'Which sections would you like?', canPickMany: true })
  if (!selectedSections) return

  const sections = toPickedKeys(selectedSections)

  return { title, sections }
}

• Notice there are several variables globally available, but ignore that for now. More on that below.
• Paste this into {root}/.templates/Documentation/Document.md:

# ${title}

${sections.Features ? '## Features\n- ' : ''}

${sections.Settings ? '## Settings\n- ' : ''}

${sections.KnownIssues ? '## Known issues\n- ' : ''}

• Notice we’re using JavaScript template literals syntax to interpolate values from the context object returned from pig.executeAsync(…) (they’re available globally).
• Also note that of course this document will result in a bunch of whitespace if a sectionOptions option is unselected. That’s up to you to make your rendered template pretty.

Use a template

• In VS Code, right-click a folder (or your workspace root) and select Template Pig: Use template.
  • If you only have one template, it’ll begin executing.
  • If you have more than one template, you’ll be prompted to select one.
• The selected template will then call its pig.executeAsync(…) method, which may prompt you for additional information.
• The context object returned from pig.executeAsync(…) will then be passed to pig.transformContext(…) to add any additional context.
• After that, each file in the template subfolder will be rendered with the context object returned from pig.transformContext(…).
• After all template files have been rendered, they’ll be saved to disk.
  • Well, there is one step before that. More on that below.

pig.executeAsync(paths)

Implement this method to prompt the user for dynamic information. See the Global scope section below for ways you can prompt the user. This method should return an object that can be made available to your template items; all the top-level keys will be available globally in your template items. If you want to abort the template instantiation process, return a falsy value. paths is an object with two keys:

• paths.workspaceUri is your project’s root folder.
• paths.targetUri is where the template was instantiated (typically which folder was right-clicked).

pig.transformContext(context)

While you’re developing your template, you’ll likely want to test it early and often. Once you get the prompt flow down, you’ll likely start working on your template items. However, testing them over and over can become tedious if you have to keep filling out your form. We’ve got you covered! After you successfully complete a form, we keep track of the context object returned from pig.executeAsync(…). But, sometimes, you want to add more context to be available to your template items. That’s where pig.transformContext(…) comes in. When you rerun the last template, that context object will get passed to your (potentially new/updated) pig.transformContext(…) method. Whatever you return will actually be the context object available to your template items. For this reason, it is recommended that pig.executeAsync(…) return the raw answers to your prompts and then pig.transformContext(…) can add in whatever manipulations you may need — pascalCase()ing something, kebabCase()ing something else, whatever. Here’s an example:

pig.transformContext = ctx => ({
  ...ctx,
  pcName: pascalCase(ctx.name),
  kbName: kebabCase(ctx.name),
})

Setting a template file/folder’s destination path

So far you’ve seen being able to right-click a folder and instantiate your template there. But, what if you want some files to wind up there, but others need to go in specific places in your project? That’s where pig.getDestinationPath(…) comes in! Just add something like this in your .pig.js file:

// Executed after all files were rendered to determine where to save them to.
// Called for each source path found in your template, following the rules mentioned for `getFolderContents(uri)` below.
pig.getDestinationPath = (entry, context, paths) => {
  // `entry` is an object representing a file or folder.
  // `entry.sourcePath` is a string that will be relative to this template subfolder (no leading forward slash).
  // `entry.uri` is a `file`-schemed VS Code Uri object pointing to this item.
  // `entry.dirent` is a Node.js fs.Dirent object related to this item. You can determine if it’s a file or folder by using `entry.dirent.isFile()` or `entry.dirent.isDirectory()`.
  // `context` is the value your `pig.transformContext(…)` returned.
  // `paths.workspaceUri` is your project’s root folder.
  // `paths.targetUri` is where the template was instantiated (typically which folder was right-clicked).
  // Keep in mind this `switch`’s `case`s are case-sensitive!
  const { sourcePath } = entry
  switch (sourcePath) {
    // Here we’re creating a subfolder "docs" within the folder the user right-clicked.
    // We’re also renaming the file to something more descriptive.
    case 'Document.md': return `docs/${context.title}.md`
    // Here the leading forward slash tells Template Pig to place the file relative
    // to the workspace root. You’ll also notice we have Lodash available to our disposal!
    case 'Test.js': return `/tests/${_.kebabCase(context.name)}.test.js`
    // You can return any falsy value to omit a file from being written to disk.
    // Typically you’d prompt the user in your `pig.executeAsync(…)` method, and then turn something
    // off based on their response.
    case 'MaybeIncluded.js': return context.shouldIncludeMaybeIncluded ? sourcePath : false
    // Otherwise, just plop it relative to the target (where the user right-clicked).
    default: return sourcePath
  }
}

pig.shouldOpenDocument(entry, context, paths)

Undoubtedly some of the documents you create won’t be immediately necessary to manually edit/inspect after template instantiation. To declutter your workspace, you can implement pig.shouldOpenDocument(…). Simply return a truthy value to leave the document open, or a falsy value to close it. Here’s an example:

pig.shouldOpenDocument = (entry, context, paths) => {
  // Arguments are identical to `getDestinationPath(…)` above.
  const { sourcePath } = entry
  switch (sourcePath) {
    case 'OpenMe.txt': return true
    default: return false
  }
}

Please note: This experience isn’t ideal; unfortunately, VS Code’s API doesn’t make it easy to make all of your template’s changes in a WorkspaceEdit and control whether or not a tab will show up. I’ve tried two approaches, and both have their pros and cons.

1. Create and apply a single WorkspaceEdit for the entire template. This resulted in a lot of documents being left open that should’ve been closed and forced me to put an arbitrary setTimeout to close documents. For bigger templates, that size would just have to keep increasing.
2. Create and apply a WorkspaceEdit for each file in the template. This has a lot more flickering of tabs opening and then closing, but the end state is more often what you want: open the documents that should be open, and close those that should not.

I'm currently opting for option #2 for consistency. There are a handful of related GitHub issues to fix this behavior with VS Code’s API, but it doesn’t seem like it’ll be fixed anytime soon.

Empty folders

You can also put empty folders in your template. They follow the same rules as files when passed to pig.getDestinationPath(…):

• They can be placed relative to the target.
• They can be placed relative to the workspace root.
• They can be renamed! This also means you can make a template-root-level folder actually be nested several folders deep; you just need a placeholder to tell Template Pig to ask about it in pig.getDestinationPath(…).
• Do note that git and some other version control systems (VCS) will not version this folder.
  • To work around this, you can add an empty .pignore or .pigignore file to the folder.

More on .pig.js

These values are available globally within your .pig.js file.

• pig.name, pig.detail, and pig.description are used to describe your template when the user is prompted about which template they’d like to instantiate.
  • pig.name is defaulted to the sentence-case version of your folder; you don’t have to set it!
  • pig.detail is put next to pig.name in a dimmer text. It may be cropped, but hovering it will reveal the entirety of the text.
  • pig.description is like pig.detail in all ways except it’s put below pig.name.
• log(value)
  • Logs value to the VS Code "Template Pig" output channel.

Global scope

Several useful libraries and functions are injected and available globally, both in .pig.js and your template items.

• Lodash, available as the traditional _.
• change-case (both core and some of the more useful non-core functions), available globally:
  • camelCase()
  • capitalCase()
  • constantCase()
  • dotCase()
  • headerCase()
  • isLowerCase()
  • isUpperCase()
  • localeLowerCase()
  • localeUpperCaseFirst()
  • lowerCase()
  • lowerCaseFirst()
  • noCase() (also aliased as lowerSentenceCase() and spaceCase())
  • paramCase() (also aliased as kebabCase())
  • pascalCase()
  • pathCase()
  • sentenceCase()
  • snakeCase()
  • titleCase()
  • upperCase()
  • upperCaseFirst()
    • Basically, no swapCase() or spongeCase().
• pluralize, available without needing the prefix pluralize. (i.e. these functions are global)
  • addIrregularRule()
  • addPluralRule()
  • addSingularRule()
  • addUncountableRule()
  • isPlural()
  • isSingular()
  • plural()
  • singular()
• From VS Code API:
  • showQuickPick()
  • showInputBox()
  • QuickPickItemKind
    • Official documentation is currently lacking, but there's two useful values: Separator and Default.
  • QuickInputButtons
• Template Pig specific:
  • option(label)
    • Builds an option object with the given label, and a key that’s the pascalCase-ified label.
    • The key is useful in combination with toPickedKeys() below.
  • prepicked(label)
    • Builds an option object like option(label) but also sets picked: true.
  • toPickedKeys(array)
    • Converts [{ key: 'Foo' }, { key: 'Bar' }, { key: 'Baz' }] to { Foo: true, Bar: true, Baz: true }.
    • You likely will get an array similar to above when calling showQuickPick(options, { canPickMany: true }).
    • This is useful so your templates can simply ${selected.Foo ? 'Foo stuff' : ''} instead of selected.includes('Foo').
  • getFileContent(uri)
    • Returns the file’s content as a string, read with UTF-8 encoding.
    • Returns null if there’s an error reading the file.
  • getFolderContents(uri, options = {…})
    • Returns an async generator
    • Yields files and folders underneath the uri.
    • Skips files named .pig.js, .pignore, and .pigignore.
    • options.yieldNonEmptyFolders: defaults to false.
      • By default, only yields folders when they don’t yield child items. That is, it’ll only yield a folder that’s either empty or only contains some combination of the aforementioned specific files. Or has symbolic links or other weird stuff (that’d be skipped).
    • options.maxDepth: defaults to Infinity. Specifies how many folders deep would you like to go.
  • getRelativePath(ancestorUri, descendantUri)
    • Given file: scheme Uris pointing to C:\Foo\Bar and C:\Foo\Bar\Baz\Qux.txt, returns the string 'Baz/Qux.txt'
    • Does not handle cases when descendantUri is actually a sibling or ancestor's descendant.
  • toFileUri(path)
    • Returns path normalized then wrapped in a VS Code Uri object with the file: scheme.

Template item syntax

Everything in a template item is evaluated as a JavaScript template literal. However, sometimes it can be useful to set up file-specific variables or helper functions. For example, if you have a highly dynamic template that conditionally adds several contiguous sections and the whitespace between them is important, that can result in a lot of ${…}${…}${…}${…} on a single line. Reading one really long line of code isn’t fun.

Enter the <pig> tag! If you place one of these at the beginning of your template item, you can add additional JavaScript between it and its corresponding </pig>. A single immediate newline following the </pig> will be stripped (if existent). Everything after that is your template item content.

Here’s a simple example template item leveraging this feature:

<pig>
  // Assume `methodNames` came from `pig.executeAsync(…)`'s return context.
  const allMethods = methodNames.map(m => `function ${m}() {\n  \n}`).join('\n\n')
</pig>
public class ${name} {
${allMethods}
}

Extension settings

This extension acknowledges the following settings:

• templatePig.templatesPath
  • The path for workspace-specific templates.
  • Defaults to ".templates", which is effectively "{root}/.templates".

• templatePig.globalTemplatesPath
  • The path for globally useful templates.
  • Defaults to null.

Known issues

• All rendered template files are opened after 1 second.
• Files are always overwritten without prompt.

Release notes

See CHANGELOG.md