In Mustache templating is there an elegant way of expressing a comma separated list without the trailing comma?

Question

I am using the Mustache templating library and trying to generate a comma separated list without a trailing comma, e.g.

red, green, blue

Answer 1

I'm using custom functions for that, in my case when working with dynamic SQL queries.

    $(document).ready(function () {
    var output = $("#output");    
    var template = $("#test1").html();
    var idx = 0;
    var rows_count = 0;
    var data = {};
    
    data.columns = ["name", "lastname", "email"];
    data.rows  = [
      ["John", "Wick", "john.wick@hotmail.com"],
      ["Donald", "Duck", "donald.duck@ducks.com"],
      ["Anonymous", "Anonymous","jack.kowalski@gmail.com"]
    ];

    data.rows_lines = function() {
      let rows = this.rows;
      let rows_new = [];
      for (let i = 0; i < rows.length; i++) {
        let row = rows[i].map(function(v) {
            return `'${v}'`
        })
        rows_new.push([row.join(",")]);
      }
      rows_count = rows_new.length;
      return rows_new
    }

    data.last = function() {
        return idx++ === rows_count-1; // omit comma for last record
    }
    
    var html = Mustache.render(template, data);
    output.append(html);

});

Mustache example: Generate SQL query (last item support - omit comma for last insert)

https://jsfiddle.net/tmdoit/4p5duw70/8/