DustJs - Helpers rendering - dust.js

Question

I start with DustJs in KrakenJs environment and i have some troubles with Dust helpers.
In fact, i want to create a helper that can create for me a simple bootstrap button.
Here is my code :
var dust = require('dustjs-linkedin');
if (!dust.helpers)
dust.helpers = {};
dust.helpers.bootstrapButton = function (chunk, context, bodies, params) {
var body = bodies.block || '',
options = params || {},
btnStyle = options.style || 'default',
btnClass = options.class || '',
btnSize = options.size || '';
btnStyle = 'btn btn-' + btnStyle;
if (btnSize)
btnSize = 'btn-' + btnSize;
return chunk.write('<button class="' + btnClass + btnStyle + btnSize + '">' + body + '</button>');
};
And when i call this helper i have the render function for body instead of the final text for body (button content : "function body_3(chk,ctx){ctx=ctx.shiftBlocks(blocks);return chk.write("test");}")
I tried to user chunk.render but i have an error because my final html is not a function like body.
Do you have any idea ?
Regards,
Guillaume

Answer 1

The body is an unevaluated chunk which you need to evaluate before you can concatenate it with your strings.
var curChunk = chunk.data.join(); // Capture anything in chunk prior to this helper
chunk.data = []; // Empty current chunk
var body = bodies.block(chunk).data.join() || '', // Evaluate block and make a string of it
.......
return chunk.write(curChunk + '<button class="' + btnClass + btnStyle + btnSize + '">' + body + '</button>'); // Prefix output with any earlier chunk contents and then build your tag.