Rename transpileJS to babel

And add a test.

Updates #5764

content/en/hugo-pipes/babel.md

@@ -0,0 +1,55 @@
+---
+title: Babel
+description: Hugo Pipes can process JS files with Babel.
+date: 2019-03-21
+publishdate: 2019-03-21
+lastmod: 2019-03-21
+categories: [asset management]
+keywords: []
+menu:
+  docs:
+    parent: "pipes"
+    weight: 49
+weight: 49
+sections_weight: 49
+draft: false
+---
+
+Any JavaScript resource file can be transpiled to another JavaScript version using `resources.Babel` which takes for argument the resource object and an optional dict of options listed below. Babel uses the [babel cli](https://babeljs.io/docs/en/babel-cli).
+
+
+{{% note %}}
+Hugo Pipe's Babel requires the `@babel/cli` and `@babel/core` JavaScript packages to be installed in the project or globally (`npm install -g @babel/cli @babel/core`) along with any Babel plugin(s) or preset(s) used (e.g., `npm install @babel/preset-env --save-dev`).
+
+If you are using the Hugo Snap package, Babel and plugin(s) need to be installed locally within your Hugo site directory, e.g., `npm install @babel/cli @babel/core --save-dev` without the `-g` flag.
+{{% /note %}}
+
+### Options
+
+config [string]
+: Path to the Babel configuration file. Hugo will, by default, look for a `babel.config.js` in your project. More information on these configuration files can be found here: [babel configuration](https://babeljs.io/docs/en/configuration).
+
+minified [bool]
+: Save as much bytes as possible when printing
+
+noComments [bool]
+: Write comments to generated output (true by default)
+
+compact [bool]
+: Do not include superfluous whitespace characters and line terminators. Defaults to `auto` if not set.
+
+verbose [bool]
+: Log everything
+
+### Examples
+
+```go-html-template
+{{- $transpiled := resources.Get "scripts/main.js" | babel  -}}
+```
+
+Or with options:
+
+```go-html-template
+{{ $opts := dict "noComments" true }}
+{{- $transpiled := resources.Get "scripts/main.js" | babel $opts -}}
+```