slint-ui/slint · warning

Unexpected STRING value type

Error message

Unexpected STRING value type: ${typeof value} for ${variable.name}

What it means

A Figma variable declared as STRING resolved to a value that is not a string nor a resolvable string reference. The exporter warns and substitutes the default value for a string type instead of failing.

Solutions

1. Fix the alias in Figma so the STRING variable references a string variable or holds a literal string
2. Refresh/re-resolve the variables snapshot so references are expanded before formatting
3. Trace earlier 'Failed to resolve STRING reference' warnings to the unresolved alias
4. Validate variable.resolvedType classification against the actual Figma type

Example fix

// before
formattedValue = getDefaultValueForType("string");
// after
if (typeof value !== "string") {
  exportInfo.errors.add(`STRING variable ${variable.name} has non-string value`);
  formattedValue = ""; // or throw, depending on strictness
}

if (variable.resolvedType === "STRING" && value !== null && typeof value !== "string" && typeof (value as any)?.id !== "string") {
  throw new Error(`STRING variable ${variable.name} has invalid value`);
}

function isStringValue(v: unknown): boolean {
  return typeof v === "string" || (typeof v === "object" && v !== null && typeof (v as any).id === "string");
}

try {
  formattedValue = formatString(value);
} catch (e) {
  exportInfo.errors.add(`STRING format failed for ${variable.name}: ${e.message}`);
  formattedValue = getDefaultValueForType("string");
}

When it happens

Trigger: exportFigmaVariablesToSeparateFiles handles a STRING variable whose value is typeof neither 'string' nor an expandable reference object (e.g. alias to a non-string variable, null, undefined).

Common situations: String variable aliased to a color/float variable whose resolution failed; Figma API shape change; stale cached resolved data after the variable type changed in Figma.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Unexpected BOOLEAN value type
• Unexpected FLOAT value type
• Missing resolved data for
• [getVariablePathString] Collection not found for variable ID
• Mode mismatch for variable

AI-assisted analysis of slint-ui/slint@bb937076de (2026-09-16). Data as JSON: /api/errors/2d26f1d64a2c5083. Report an issue: GitHub.

Appendix: source

Thrown at tools/figma-inspector/backend/utils/export-variables.ts:1168

                                if (resolvedValue) {
                                    formattedValue = resolvedValue;
                                    const referenceName =
                                        variableNamesById.get(value.id) ||
                                        value.id;
                                    comment = `Resolved from reference ${referenceName}`;
                                } else {
                                    formattedValue =
                                        getDefaultValueForType("string");
                                    const referenceName =
                                        variableNamesById.get(value.id) ||
                                        value.id;
                                    comment = `Failed to resolve reference ${referenceName}, using default`;
                                    exportInfo.warnings.add(
                                        `Failed to resolve STRING reference ${value.id} for ${variable.name}.${modeName}`,
                                    );
                                }
                            } else {
                                console.warn(
                                    `Unexpected STRING value type: ${typeof value} for ${variable.name}`,
                                );
                                formattedValue =
                                    getDefaultValueForType("string");
                            }
                        } else if (variable.resolvedType === "BOOLEAN") {
                            if (typeof value === "boolean") {
                                formattedValue = value ? "true" : "false";
                            } else if (
                                typeof value === "object" &&
                                value &&
                                "type" in value &&
                                value.type === "VARIABLE_ALIAS"
                            ) {
                                // Resolve reference to concrete value immediately
                                const resolvedValue =
                                    await followChainToConcreteValue(
                                        value.id,

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