PSMustache

PSMustache is an implementation of the Mustache template system purely in PowerShell without any external dependencies. It requires at least PowerShell 5.1 and runs great in later Versions. PSMustache currently passes all Spec-Tests up to the current Mustache-Spec-Release, except the Parent-Tags.

In Reference to mustache.js:

Mustache is a logic-less template syntax. It can be used for HTML, config files, source code - anything. It works by expanding tags in a template using values provided in a hashtables, PSCustomObjects or even mixed.

We call it "logic-less" because there are no if statements, else clauses, or for loops. Instead there are only tags. Some tags are replaced with a value, some nothing, and others a series of values.

For a list of implementations and tips, see http://mustache.github.io/.

Installation

The prefered way is to install the latest published version for PowershellGallary via

Install-Module -Name PSMustache

Alternatively you can just clone this repo or download a release and import the Module via

Import-Module .\PSMustache.psd1

Usage

PSMustache has only one single but very powerfull CMDlet ConvertFrom-MustacheTemplate with the following parameters:

-Template takes the Mustache-Template as a string. In more complex scenarios you'll usually get the template from e.g. a file
-Values are the data as a hashtable or PSCustomObject. You can have as many nested levels as needed.

Optional Parameters:

-Partials kind of named subtemplates or includes.
-DelimiterLeft sets a different opening delimiter when {{ is already used
-DelimiterRight sets a different closing delimiter when }} is already used

For a complete language-agnostic overview you can also refer to mustache(5)

Interpolation

{{Variable}} Interpolation with simple variables.

PS> ConvertFrom-MustacheTemplate -Template 'Hi {{Name}}!' -Values @{Name='Joe'}

Hi Joe!

{{Variable}} Interpolation with different delimiters.

PS> ConvertFrom-MustacheTemplate -Template 'Hi [[Name]], {{keepThisUntouched}}!' -Values @{Name='Joe'} -DelimiterLeft '[[' -DelimiterRight ']]'

Hi Joe, {{keepThisUntouched}}!

Interpolation with nested hashtables

PS> $values = @{
    person = @{
        name = 'Joe'
        country = 'Germany'
    }
}
PS> ConvertFrom-MustacheTemplate -Template 'Hi {{person.name}} from {{person.country}}!' -Values $values

Hi Joe from Germany!

Sections & Inverts

{{#SectionName}} Sections are used to iterate through arrays when they are not empty. They must be closed with the closing Tag {{/SectionName}}. When a section is iterated, the current element can be accessed by the name or, if it containts only one element, through the dot-operator.

When you want to output something when an element is NOT found or is empty, you can use inverted sections. {{^SectionName}} which must also be closed with a closing Tag {{/SectionName}}

PS> $values = @{
    persons = @(
        @{
            name = 'Joe'
            Repos = @('FirstRepo', 'SecondRepo')
        },
        @{
            name = 'James'
        }
    )
}
PS> $template = @"
Known Repo List
----------------
{{#persons}}
 * {{Name}}:
 {{#repos}}
   + {{.}}
 {{/repos}}
 {{^repos}}
   - No repos
 {{/repos}}
{{/persons}}
"@
PS> ConvertFrom-MustacheTemplate -Template $template -Values $values

Known Repo List
----------------
 * Joe:
   + FirstRepo
   + SecondRepo
 * James:
   - No repos

Comments

{{! This is a comment}} Comment-Tags are just completely removed from the template. When they are the only content in a line, the whole line is removed

PS> ConvertFrom-MustacheTemplate -Template 'Hi {{Name}}{{! This is a comment}}! ' -Values @{Name='Joe'}

Hi Joe