process.js - Yatate

Plain JavaScript, run via flutter_js. Decides which layout partials actually get included when a PDF is generated, and can prepare presentation data for blocks to use. Optional - a project with nothing conditional doesn't need it. Edited via the Script Editor. Runs after validate.js passes - see the full processing pipeline.

APIs available

Name	Type	Meaning
`inputs`	object	Same submitted-data map `validate.js` sees. Assigning a new property onto it forwards that value to every block (see below); reassigning an existing submitted field's value has no effect.
`overlay(filename)`	function	Queues a layout partial (path relative to the project root) to be merged into this generation run.

overlay("overlay.json");             // always include the base layout

if (inputs["is_certified"]) {
  overlay("certified_badge.json");   // only when the checkbox is on
}

If process.js doesn't exist at all, the app behaves as if it contained exactly overlay("overlay.json");.
A partial named that doesn't exist is silently skipped, not an error.
Every block id across everything actually included in one run must be unique.

Handing computed data to blocks

Compute presentation data here instead of writing a long formula inline in a block's own JSON, by assigning it as a new property on inputs:

inputs.gridData = [];
for (var i = 0; i < inputs.options.length; i++) {
  var option = inputs.options[i];
  inputs.gridData.push(
    { text: (i + 1) + '. ' + option.description },
    { text: '$' + option.price, 'text-align': 'right' }
  );
}

overlay("overlay.json");

(Turning a repeating group into grid cells specifically has its own walkthrough: Generating Grid Data.)

A block then references it directly:

{ "id": "options_grid", "type": "grid", "columns": 2, "data": "inputs.gridData" }

Two behaviors worth knowing:

Only new property names get forwarded. Reassigning an existing submitted field (e.g. inputs.msrp = '$' + inputs.msrp) is silently dropped before rendering - a block still sees the original value. This is deliberate (the app's own date formatting, for example, would otherwise be bypassable). Always compute into a fresh name.
process.js and a block's own expression run in separate scripting contexts - the only bridge between them is a new inputs.* property. A plain local variable (var x = 5;) never reaches a block.