src/shared/lib/utils/clampNumber/clampNumber.ts

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+/**
+ * Clamp a number within a range.
+ * @param value The number to clamp.
+ * @param min minimum value
+ * @param max maximum value
+ * @returns The clamped number.
+ */
+export function clampNumber(value: number, min: number, max: number): number {
+    return Math.min(Math.max(value, min), max);
+}

src/shared/lib/utils/getDecimalPlaces/getDecimalPlaces.ts

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+/**
+ * Get the number of decimal places in a number
+ *
+ * For example:
+ * - 1 -> 0
+ * - 0.1 -> 1
+ * - 0.01 -> 2
+ * - 0.05 -> 2
+ *
+ * @param step - The step number to analyze
+ * @returns The number of decimal places
+ */
+export function getDecimalPlaces(step: number): number {
+    const str = step.toString();
+    const decimalPart = str.split('.')[1];
+    return decimalPart ? decimalPart.length : 0;
+}

src/shared/lib/utils/roundToStepPrecision/roundToStepPrecision.ts

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+import { getDecimalPlaces } from '$shared/lib/utils';
+
+/**
+ * Round a value to the precision of the given step
+ *
+ * This fixes floating-point precision errors that occur with decimal steps.
+ * For example, with step=0.05, adding it repeatedly can produce values like
+ * 1.3499999999999999 instead of 1.35.
+ *
+ * We use toFixed() to round to the appropriate decimal places instead of
+ * Math.round(value / step) * step, which doesn't always work correctly
+ * due to floating-point arithmetic errors.
+ *
+ * @param value - The value to round
+ * @param step - The step to round to (defaults to 1)
+ * @returns The rounded value
+ */
+export function roundToStepPrecision(value: number, step: number = 1): number {
+    if (step <= 0) {
+        return value;
+    }
+    const decimals = getDecimalPlaces(step);
+    return parseFloat(value.toFixed(decimals));
+}