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Editing Plugin Files

How trial parameters work in core

The entry point of a trial using the core plugin is under src/core.js.

The two arguments are display_element, the html element for trial and trial, the object containing all the trial's parameters.

Next, you'll see something like the following. This takes the fields from trial (or a default value) and adds them as fields of the class. This it is accessible whenever needed as this.whatever.

this.trial = trial;
this.stimuli = setParameter(trial.stimuli, [], null);
this.randomize = setParameter(trial.randomize, false, "boolean");
// ...etc

Then in the showRecall method, these values are used to do the trial.

For instance, rendering buttons gets the following arguments. Here, stimulus is one item from the array of this.stimulus.

responseView = new ResponseButtonView(

Here is the corresponding file.

class InputView {
    constructor($displayElement, coreInstance, dataInstance, stimulus) {
// ... etc

So, you have access to all the fields as before. For instance coreInstance.randomize is the same as this.randomize in core.js and stimulus is the current object in the this.stimulus array.

This is passed further down to the container which can access the stimulus parameters the same way.

class ButtonResponseContainer extends ResponseContainer {
    constructor(generatorInstance, buttonLabel, stimulus, dataInstance) {
// ...etc

Adding new parameters

Take the following hypothetical trial, where foo, bar, and foobar are new paremeters we want to add.

const start = {
  type: "pcllab-core",
  stimuli: [
      foo: true,
      bar: 26,
  foobar: "Look at me!",
  show_button: true,
  button_text: "Continue",
  response_count: 0,
  minimum_time: 7000,

foo and bar, will be accessible as or in the showRecall method and wherever stimulus is passed.

For, foobar, you can add a line like this.foobar = setParameter(trial.foobar, "default string", "string");. Then this.foobar, will be accessible anywhere in core.js.