smilingleo / wig

Enhanced Mustache template engine

Wig

An enhanced Mustache template engine.

Why Wig?

Mustache is a logic-less template engine. It is a great tool for generating HTML, but it is not very flexible. Wig is a Mustache template engine that adds some functions to transform data and control the flow of the template.

Usage

String template = """
        {{#Invoice}}
            Invoices with charges greater than $100:
            {{#InvoiceItems|FilterByValue(ChargeAmount,GT,100)}}
                {{ChargeName}} - {{ChargeAmount}}
            {{/InvoiceItems|FilterByValue(ChargeAmount,GT,100)}}

            Total charge amount by charge name:
            {{#InvoiceItems|GroupBy(ChargeName)}}
                {{ChargeName}} - {{_Group|Sum(ChargeAmount)|Round(2)|Localise}}
            {{/InvoiceItems|GroupBy(ChargeName)}}
        {{/Invoice}}
        """;
Map<String, Object> data = Map.of(
        "Invoice", Map.of(
                "InvoiceItems", List.of(
                        Map.of("ChargeName", "Charge 1", "ChargeAmount", 100, "ServiceDate", "2021-01-01"),
                        Map.of("ChargeName", "Charge 1", "ChargeAmount", 150, "ServiceDate", "2021-02-01"),
                        Map.of("ChargeName", "Charge 2", "ChargeAmount", 200, "ServiceDate", "2021-01-01"),
                        Map.of("ChargeName", "Charge 2", "ChargeAmount", 250, "ServiceDate", "2021-02-01")
                )
        )
);
Wig wig = new Wig();
System.out.println(wig.render(template, data));

Decorator

A decorator is a function that takes its left side as input and returns a value. Decorators are used to transform data.

Decorators cannot be used standalone, they must be used with an input. For example:

var template = "{{Name|Substr(0,3)}}";
var data = Map.of("Name", "John");

Built-in Decorators

• Concat
• Default
• Format
• GroupBy
• Localise
• Map
• FlatMap
• Max
• Min
• Sum
• Uniq
• Round
• SortBy
• FilterByValue
• FilterByRef
• Symbol
• DateAdd
• EqualToVal
• IsBlank
• IsEmpty
• Last
• Size
• First
• Last
• Nth
• Skip

Function

Different from decorators, functions can be used standalone. For example:

{{Fn_Today}}

Functions are named with the prefix Fn_.

Built-in Functions

• Fn_Today
• Fn_Calc

Command

Different from decorators and functions, commands have no output, they are used to declare variables or construct new objects.

See test cases for more examples.