jsPsych/packages/plugin-maxdiff/src/index.ts
2024-11-01 17:45:19 -04:00

336 lines
12 KiB
TypeScript

import { JsPsych, JsPsychPlugin, ParameterType, TrialType } from "jspsych";
import { version } from "../package.json";
const info = <const>{
name: "maxdiff",
version: version,
parameters: {
/** An array of one or more alternatives of string type to fill the rows of the maxdiff table. If `required` is true,
* then the array must contain two or more alternatives, so that at least one can be selected for both the left
* and right columns. */
alternatives: {
type: ParameterType.STRING,
array: true,
default: undefined,
},
/** An array with exactly two labels of string type to display as column headings (to the left and right of the
* alternatives) for responses on the criteria of interest. */
labels: {
type: ParameterType.STRING,
array: true,
default: undefined,
},
/** If true, the display order of `alternatives` is randomly determined at the start of the trial. */
randomize_alternative_order: {
type: ParameterType.BOOL,
default: false,
},
/** HTML formatted string to display at the top of the page above the maxdiff table. */
preamble: {
type: ParameterType.HTML_STRING,
default: "",
},
/** Label of the button to submit response. */
button_label: {
type: ParameterType.STRING,
default: "Continue",
},
/** If true, prevents the user from submitting the response and proceeding until a radio button in both the left and right response columns has been selected. */
required: {
type: ParameterType.BOOL,
default: false,
},
},
data: {
/** The response time in milliseconds for the participant to make a response. The time is measured from when the maxdiff table first
* appears on the screen until the participant's response. */
rt: {
type: ParameterType.INT,
},
/** An object with two keys, `left` and `right`, containing the labels (strings) corresponding to the left and right response
* columns. This will be encoded as a JSON string when data is saved using the `.json()` or `.csv()` functions. */
labels: {
type: ParameterType.COMPLEX,
parameters: {
left: {
type: ParameterType.STRING,
},
right: {
type: ParameterType.STRING,
},
},
},
/** An object with two keys, `left` and `right`, containing the alternatives selected on the left and right columns.
* This will be encoded as a JSON string when data is saved using the `.json()` or `.csv()` functions. */
response: {
type: ParameterType.COMPLEX,
parameters: {
left: {
type: ParameterType.STRING,
},
right: {
type: ParameterType.STRING,
},
},
},
},
citations: "__CITATIONS__",
};
type Info = typeof info;
/**
* The maxdiff plugin displays a table with rows of alternatives to be selected for two mutually-exclusive categories,
* typically as 'most' or 'least' on a particular criteria (e.g. importance, preference, similarity). The participant
* responds by selecting one radio button corresponding to an alternative in both the left and right response columns.
* The same alternative cannot be endorsed on both the left and right response columns (e.g. 'most' and 'least') simultaneously.
*
* @author Angus Hughes
* @see {@link https://www.jspsych.org/latest/plugins/maxdiff/ maxdiff plugin documentation on jspsych.org}
*/
class MaxdiffPlugin implements JsPsychPlugin<Info> {
static info = info;
constructor(private jsPsych: JsPsych) {}
trial(display_element: HTMLElement, trial: TrialType<Info>) {
var html = "";
// inject CSS for trial
html += '<style id="jspsych-maxdiff-css">';
html +=
".jspsych-maxdiff-statement {display:block; font-size: 16px; padding-top: 40px; margin-bottom:10px;}" +
"table.jspsych-maxdiff-table {border-collapse: collapse; padding: 15px; margin-left: auto; margin-right: auto;}" +
"table.jspsych-maxdiff-table td, th {border-bottom: 1px solid #dddddd; text-align: center; padding: 8px;}" +
"table.jspsych-maxdiff-table tr:nth-child(even) {background-color: #dddddd;}";
html += "</style>";
// show preamble text
if (trial.preamble !== null) {
html +=
'<div id="jspsych-maxdiff-preamble" class="jspsych-maxdiff-preamble">' +
trial.preamble +
"</div>";
}
html += '<form id="jspsych-maxdiff-form">';
// add maxdiff options ///
// first generate alternative order, randomized here as opposed to randomizing the order of alternatives
// so that the data are always associated with the same alternative regardless of order.
var alternative_order = [];
for (var i = 0; i < trial.alternatives.length; i++) {
alternative_order.push(i);
}
if (trial.randomize_alternative_order) {
alternative_order = this.jsPsych.randomization.shuffle(alternative_order);
}
// Start with column headings
var maxdiff_table =
'<table class="jspsych-maxdiff-table"><tr><th id="jspsych-maxdiff-left-label">' +
trial.labels[0] +
'</th><th></th><th id="jspsych-maxdiff-right-label">' +
trial.labels[1] +
"</th></tr>";
// construct each row of the maxdiff table
for (var i = 0; i < trial.alternatives.length; i++) {
var alternative = trial.alternatives[alternative_order[i]];
// add alternative
maxdiff_table +=
'<tr><td><input class= "jspsych-maxdiff-alt-' +
i.toString() +
'" type="radio" name="left" data-name = ' +
alternative_order[i].toString() +
" /><br></td>";
maxdiff_table +=
'<td id="jspsych-maxdiff-alternative-' + i.toString() + '">' + alternative + "</td>";
maxdiff_table +=
'<td><input class= "jspsych-maxdiff-alt-' +
i.toString() +
'" type="radio" name="right" data-name = ' +
alternative_order[i].toString() +
" /><br></td></tr>";
}
maxdiff_table += "</table><br><br>";
html += maxdiff_table;
// add submit button
var enable_submit = trial.required == true ? 'disabled = "disabled"' : "";
html +=
'<input type="submit" id="jspsych-maxdiff-next" class="jspsych-maxdiff jspsych-btn" ' +
enable_submit +
' value="' +
trial.button_label +
'"></input>';
html += "</form>";
display_element.innerHTML = html;
// function to control responses
// first checks that the same alternative cannot be endorsed in the left and right columns simultaneously.
// then enables the submit button if the trial is required.
const left_right = ["left", "right"];
left_right.forEach((p) => {
// Get all elements either 'left' or 'right'
document.getElementsByName(p).forEach((alt) => {
alt.addEventListener("click", () => {
// Find the opposite (if left, then right & vice versa) identified by the class (jspsych-maxdiff-alt-1, 2, etc)
var op = alt["name"] == "left" ? "right" : "left";
var n = document.getElementsByClassName(alt.className).namedItem(op);
// If it's checked, uncheck it.
if (n["checked"]) {
n["checked"] = false;
}
// check response
if (trial.required) {
// Now check if one of both left and right have been enabled to allow submission
var left_checked = Array.prototype.slice
.call(document.getElementsByName("left"))
.some((c: HTMLInputElement) => c.checked);
var right_checked = Array.prototype.slice
.call(document.getElementsByName("right"))
.some((c: HTMLInputElement) => c.checked);
if (left_checked && right_checked) {
(document.getElementById("jspsych-maxdiff-next") as HTMLInputElement).disabled =
false;
} else {
(document.getElementById("jspsych-maxdiff-next") as HTMLInputElement).disabled = true;
}
}
});
});
});
// Get the data once the submit button is clicked
// Get the data once the submit button is clicked
display_element.querySelector("#jspsych-maxdiff-form").addEventListener("submit", (e) => {
e.preventDefault();
// measure response time
var endTime = performance.now();
var response_time = Math.round(endTime - startTime);
// get the alternative by the data-name attribute, allowing a null response if unchecked
function get_response(side) {
var col = display_element.querySelectorAll('[name="' + side + '"]:checked')[0];
if (col === undefined) {
return null;
} else {
var i = parseInt(col.getAttribute("data-name"));
return trial.alternatives[i];
}
}
// data saving
var trial_data = {
rt: response_time,
labels: { left: trial.labels[0], right: trial.labels[1] },
response: { left: get_response("left"), right: get_response("right") },
};
// next trial
this.jsPsych.finishTrial(trial_data);
});
var startTime = performance.now();
}
simulate(
trial: TrialType<Info>,
simulation_mode,
simulation_options: any,
load_callback: () => void
) {
if (simulation_mode == "data-only") {
load_callback();
this.simulate_data_only(trial, simulation_options);
}
if (simulation_mode == "visual") {
this.simulate_visual(trial, simulation_options, load_callback);
}
}
private create_simulation_data(trial: TrialType<Info>, simulation_options) {
const choices = this.jsPsych.randomization.sampleWithoutReplacement(trial.alternatives, 2);
const response = { left: null, right: null };
if (!trial.required && this.jsPsych.randomization.sampleBernoulli(0.1)) {
choices.pop();
if (this.jsPsych.randomization.sampleBernoulli(0.8)) {
choices.pop();
}
}
if (choices.length == 1) {
if (this.jsPsych.randomization.sampleBernoulli(0.5)) {
response.left = choices[0];
} else {
response.right = choices[0];
}
}
if (choices.length == 2) {
response.left = choices[0];
response.right = choices[1];
}
const default_data = {
rt: this.jsPsych.randomization.sampleExGaussian(3000, 300, 1 / 300, true),
labels: trial.labels,
response: response,
};
const data = this.jsPsych.pluginAPI.mergeSimulationData(default_data, simulation_options);
this.jsPsych.pluginAPI.ensureSimulationDataConsistency(trial, data);
return data;
}
private simulate_data_only(trial: TrialType<Info>, simulation_options) {
const data = this.create_simulation_data(trial, simulation_options);
this.jsPsych.finishTrial(data);
}
private simulate_visual(trial: TrialType<Info>, simulation_options, load_callback: () => void) {
const data = this.create_simulation_data(trial, simulation_options);
const display_element = this.jsPsych.getDisplayElement();
this.trial(display_element, trial);
load_callback();
//@ts-ignore something about symbol iterators?
const list = [...display_element.querySelectorAll("[id^=jspsych-maxdiff-alternative]")].map(
(x) => {
return x.innerHTML;
}
);
if (data.response.left !== null) {
const index_left = list.indexOf(data.response.left);
this.jsPsych.pluginAPI.clickTarget(
display_element.querySelector(`.jspsych-maxdiff-alt-${index_left}[name="left"]`),
data.rt / 3
);
}
if (data.response.right !== null) {
const index_right = list.indexOf(data.response.right);
this.jsPsych.pluginAPI.clickTarget(
display_element.querySelector(`.jspsych-maxdiff-alt-${index_right}[name="right"]`),
(data.rt / 3) * 2
);
}
this.jsPsych.pluginAPI.clickTarget(
display_element.querySelector("#jspsych-maxdiff-next"),
data.rt
);
}
}
export default MaxdiffPlugin;