ankane/pghero · error · Error

noUiSlider: ' ' is required.

Error message

noUiSlider: '{name}' is required.

What it means

During create(), noUiSlider runs every option through a test suite; options flagged as required (tests[name].r, notably start) must be present. isSet(options[name]) is false and no default exists, so the loop throws "noUiSlider: '{name}' is required." with the option name interpolated. In practice the name is almost always 'start' - the initial handle value(s).

Solutions

1. Add start: [value] (array) or start: value to the options, e.g. noUiSlider.create(el, {start: [50], range: {min: 0, max: 100}})
2. If options are dynamic, default the key before calling create: options.start = options.start || [0]
3. Check the noUiSlider documentation for the current required set (start and range are the two mandatory options)

Example fix

// before
noUiSlider.create(el, { range: { min: 0, max: 100 } });

// after
noUiSlider.create(el, { start: [50], range: { min: 0, max: 100 } });

if (!Array.isArray(options.start) && !Number.isFinite(options.start)) {
  throw new TypeError("slider options must include start");
}
noUiSlider.create(el, options);

function isSliderOptions(o) {
  return !!o && (Array.isArray(o.start) ? o.start.length > 0 : Number.isFinite(o.start)) && !!o.range;
}

When it happens

Trigger: noUiSlider.create(el, {}) with no start, or create(el, {range: {min: 0, max: 100}}) where only range was supplied. Also happens when options come from a variable that is undefined or built by a function that conditionally omits start.

Common situations: Slider configuration assembled from dynamic data (user settings, JSON) where start is omitted; refactoring that renames or drops the start key; upgrading from very old noUiSlider versions where option names differed. PgHero's own dashboard always passes start, so this only bites custom code using the vendored library.

Understand the failure class

Background: "Must pass :limit option" / "Missing required option" — required option errors explained — this error's family across 41 libraries.

Related errors

• noUiSlider: 'cssClasses' must be an object.
• noUiSlider: 'values' (>= 2) required for mode 'count'.
• noUiSlider: create requires a single element, got
• noUiSlider: invalid handle number, got
• noUiSlider: Slider was already initialized.

AI-assisted analysis of ankane/pghero@7edb57986f (2026-08-21). Data as JSON: /api/errors/389a1ae1920cf6e4. Report an issue: GitHub.

Appendix: source

Thrown at app/assets/javascripts/pghero/nouislider.js:879

            keyboardSupport: true,
            cssPrefix: "noUi-",
            cssClasses: cssClasses,
            keyboardPageMultiplier: 5,
            keyboardMultiplier: 1,
            keyboardDefaultStep: 10,
        };
        // AriaFormat defaults to regular format, if any.
        if (options.format && !options.ariaFormat) {
            options.ariaFormat = options.format;
        }
        // Run all options through a testing mechanism to ensure correct
        // input. It should be noted that options might get modified to
        // be handled properly. E.g. wrapping integers in arrays.
        Object.keys(tests).forEach(function (name) {
            // If the option isn't set, but it is required, throw an error.
            if (!isSet(options[name]) && defaults[name] === undefined) {
                if (tests[name].r) {
                    throw new Error("noUiSlider: '" + name + "' is required.");
                }
                return;
            }
            tests[name].t(parsed, !isSet(options[name]) ? defaults[name] : options[name]);
        });
        // Forward pips options
        parsed.pips = options.pips;
        // All recent browsers accept unprefixed transform.
        // We need -ms- for IE9 and -webkit- for older Android;
        // Assume use of -webkit- if unprefixed and -ms- are not supported.
        // https://caniuse.com/#feat=transforms2d
        var d = document.createElement("div");
        var msPrefix = d.style.msTransform !== undefined;
        var noPrefix = d.style.transform !== undefined;
        parsed.transformRule = noPrefix ? "transform" : msPrefix ? "msTransform" : "webkitTransform";
        // Pips don't move, so we can place them using left/top.
        var styles = [
            ["left", "top"],

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