> ## Documentation Index
> Fetch the complete documentation index at: https://doc.lucidworks.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Resolve Multivalued Fields Index Stage

export const schema = {
  "type": "object",
  "title": "Resolve Multivalued Fields",
  "description": "Reduces multi-valued document fields to a single value by applying configurable resolution strategies per field or data type. Define type strategies to apply a strategy across all fields of a given type, or field strategies to target specific fields individually. Type strategies take precedence over field strategies when both are defined for the same field.",
  "properties": {
    "skip": {
      "type": "boolean",
      "title": "Skip This Stage",
      "description": "Controls whether this stage executes during pipeline processing at runtime. When set to `true`, the stage is completely bypassed and documents pass through unchanged to the next stage. Useful for A/B testing, gradual rollouts, or temporarily disabling a stage without removing it from the pipeline.",
      "default": false,
      "hints": ["advanced"]
    },
    "label": {
      "type": "string",
      "title": "Label",
      "description": "Human-readable identifier displayed in the Fusion Admin UI, monitoring dashboards, and log messages. Use descriptive labels like `Parse Product PDFs` to aid debugging and team collaboration. Labels appear in performance metrics and error reports, making it easier to identify which stage failed.",
      "hints": ["advanced"],
      "maxLength": 255
    },
    "condition": {
      "type": "string",
      "title": "Condition",
      "description": "JavaScript expression evaluated at runtime on each document to conditionally execute this stage. The expression must return `true` to execute or `false` to skip. Access document fields using `doc.getFieldValue('fieldName')` and request parameters via `request.getFirstParam('paramName')`. For example, `doc.getFieldValue('type') === 'premium'` executes this stage only for premium content.",
      "hints": ["code", "code/javascript", "advanced"]
    },
    "typeStrategy": {
      "type": "array",
      "title": "Type Strategies",
      "description": "Maps data types such as `string`, `integer`, or `double` to a resolution strategy applied to all multi-valued fields of that type. Use this to set a default resolution behavior for each data type without listing every field individually. Type strategies are applied before field strategies and override them when both apply.",
      "items": {
        "type": "object",
        "required": ["type", "resolverStrategy"],
        "properties": {
          "type": {
            "type": "string",
            "title": "Type Name",
            "enum": ["integer", "long", "float", "double", "string"]
          },
          "resolverStrategy": {
            "type": "string",
            "title": "Resolver Strategy",
            "enum": ["pick_first", "pick_last", "pick_by_creator", "concatenate_unique", "pick_min", "pick_max", "default"],
            "default": "pick_first",
            "description": "Specifies how to select a single value from a multi-valued field of the configured type. Options include `pick_first`, `pick_last`, `pick_min`, `pick_max`, `concatenate_unique`, `pick_by_creator`, and `default`. Use `pick_by_creator` in combination with a Creator Strategies entry to prefer values set by a specific upstream stage."
          }
        }
      }
    },
    "fieldStrategy": {
      "type": "array",
      "title": "Field Strategies",
      "description": "Maps individual field names to resolution strategies, overriding any type-level strategy for those fields. Use this to apply field-specific logic where the default type strategy is insufficient. Field strategies are evaluated after type strategies.",
      "items": {
        "type": "object",
        "required": ["fieldName", "resolverStrategy"],
        "properties": {
          "fieldName": {
            "type": "string",
            "title": "Field Name"
          },
          "resolverStrategy": {
            "type": "string",
            "title": "Resolver Strategy",
            "enum": ["pick_first", "pick_last", "pick_by_creator", "concatenate_unique", "pick_min", "pick_max", "default"],
            "default": "pick_first",
            "description": "Specifies how to select a single value from a multi-valued field with this name. Options include `pick_first`, `pick_last`, `pick_min`, `pick_max`, `concatenate_unique`, `pick_by_creator`, and `default`. Use `pick_by_creator` in combination with a Creator Strategies entry to prefer values set by a specific upstream stage."
          }
        }
      }
    },
    "creatorStrategy": {
      "type": "array",
      "title": "Creator Strategies",
      "description": "Maps field names to a creator name used when the `pick_by_creator` resolution strategy is selected. The creator name identifies the pipeline stage or process that originally set the field value, allowing the resolver to prefer values from a trusted source. Only applies when a type or field strategy references `pick_by_creator`.",
      "items": {
        "type": "object",
        "required": ["fieldName", "creatorName"],
        "properties": {
          "fieldName": {
            "type": "string",
            "title": "Field Name"
          },
          "creatorName": {
            "type": "string",
            "title": "Creator Name"
          }
        }
      }
    }
  },
  "category": "Field Transformation",
  "categoryPriority": 7,
  "unsafe": false
};

export const SchemaParamFields = ({schema}) => {
  const sanitize = str => {
    if (typeof str !== "string") return str;
    return str.replace(/^"(.*)"$/s, "$1").replace(/\\/g, "").replace(/"/g, "'");
  };
  const renderMd = str => {
    const s = sanitize(str);
    const text = (/[.!?]\)*$/).test(s) ? s : `${s}.`;
    return text.split(/(\*\*[^*]+\*\*|_[^_]+_|`[^`]+`)/g).map((part, i) => {
      if (part.startsWith("**")) return <strong key={i}>{part.slice(2, -2)}</strong>;
      if (part.startsWith("_")) return <em key={i}>{part.slice(1, -1)}</em>;
      if (part.startsWith("`")) return <code key={i}>{part.slice(1, -1)}</code>;
      return part;
    });
  };
  const {description, properties = {}, required: requiredProps = []} = schema;
  const visibleProps = useMemo(() => Object.entries(properties).filter(([, prop]) => !prop.hints?.includes("hidden")), [properties]);
  const renderProp = ([name, prop]) => {
    const isRequired = requiredProps.includes(name);
    const hasDefault = prop.default !== undefined;
    const rawDefault = prop.default;
    const hints = prop.hints || [];
    const isComplexDefault = hasDefault && (typeof rawDefault === "object" || typeof rawDefault === "string" && (rawDefault.length > 20 || rawDefault.includes('"')));
    const postBadges = [];
    if (prop.title) {
      postBadges.push(<><span className="text-stone-400 dark:text-stone-500">API property: </span>{name}</>);
    }
    const constraints = [];
    if (prop.minimum !== undefined && prop.maximum !== undefined) {
      constraints.push(`Range: ${prop.minimum} – ${prop.maximum}`);
    } else if (prop.minimum !== undefined) {
      constraints.push(`Min: ${prop.minimum}`);
    } else if (prop.maximum !== undefined) {
      constraints.push(`Max: ${prop.maximum}`);
    }
    if (prop.minLength !== undefined && prop.maxLength !== undefined) {
      constraints.push(`Length: ${prop.minLength} – ${prop.maxLength}`);
    } else if (prop.minLength !== undefined) {
      constraints.push(`Min length: ${prop.minLength}`);
    } else if (prop.maxLength !== undefined) {
      constraints.push(`Max length: ${prop.maxLength}`);
    }
    const fieldProps = {
      key: name,
      body: prop.title || name,
      type: prop.type,
      ...postBadges.length > 0 && ({
        post: postBadges
      }),
      ...isRequired && ({
        required: true
      }),
      ...!isComplexDefault && hasDefault ? {
        default: sanitize(String(rawDefault))
      } : {}
    };
    const isObject = prop.type === "object" && prop.properties;
    const isArrayOfObjects = prop.type === "array" && prop.items?.type === "object" && prop.items.properties;
    return <ParamField {...fieldProps}>
        {prop.description && <p>{renderMd(prop.description)}</p>}

        {prop.enum && <p>
            Allowed values: 
            {prop.enum.map((v, i) => <>{i > 0 && ", "}<code key={i}>{String(v)}</code></>)}
          </p>}

        {constraints.length > 0 && <p className="text-stone-500 dark:text-stone-400 text-sm">
            {constraints.join(" · ")}
          </p>}

        {isComplexDefault && <div className="flex">
            <p>
              <strong>Default:</strong>
            </p>
            <pre className="!my-0">
              <code>
                {JSON.stringify(rawDefault, null, 2)}
              </code>
            </pre>
          </div>}

        {isArrayOfObjects && <Expandable title="item properties">
            <SchemaParamFields schema={{
      properties: prop.items.properties,
      required: prop.items.required
    }} />
          </Expandable>}

        {isObject && <Expandable title="properties">
            <SchemaParamFields schema={{
      properties: prop.properties,
      required: prop.required
    }} />
          </Expandable>}
      </ParamField>;
  };
  return <div>
      {description && <p>{renderMd(description)}</p>}

      {visibleProps.map(renderProp)}
    </div>;
};

export const LwTemplate = ({title = "Key questions to get you started", icon = "sparkles", cta = "Powered by Agent Studio", linkHref = "https://lucidworks.com/demo/?utm_source=docs&utm_medium=referral&utm_campaign=docs_cta_ai"}) => {
  const [isLoaded, setIsLoaded] = useState(false);
  useEffect(() => {
    const timer = setTimeout(() => {
      setIsLoaded(true);
    }, 500);
    return () => clearTimeout(timer);
  }, []);
  return <div className="lw-template-container">
      <Card title={title} icon={icon}>
        {isLoaded && <span dangerouslySetInnerHTML={{
    __html: `<lw-template id="a029c1a9-28be-427e-b0e1-5d918920246a"></lw-template
            >`
  }} />}
        <Link href={linkHref} className="agent-studio-link text-left text-gray-600 gap-2 dark:text-gray-400 text-sm font-medium flex flex-row items-center hover:text-primary dark:hover:text-primary-light group-hover:text-primary group-hover:dark:text-primary-light">Powered by Lucidworks Agent Studio</Link>
      </Card>
    </div>;
};

[localhost link]: http://localhost:3000/docs/5/fusion/reference/config-ref/pipeline-stages/index-stages/multi-value-resolver-index-stage

[mintlify link]: https://doc.lucidworks.com/docs/5/fusion/reference/config-ref/pipeline-stages/index-stages/multi-value-resolver-index-stage

[old doc.lw link]: https://doc.lucidworks.com/fusion/5.9/236

The Resolve Multivalued Fields stage (previously called the Multi-Value Resolver stage) allows you to choose one value from a set of one or more field values using a set of pre-defined rules, based on either field name or field type.
For each field name or field type rule, a strategy is defined. There are 6 available strategies:

* DEFAULT: leave all values intact. This may cause problems if a field or dynamic field rule is not defined as multi-valued in the schema.
* PICK\_FIRST: choose the first value and discard all others.
* PICK\_LAST: choose the last value and discard all others.
* PICK\_BY\_CREATOR: based on the name of the "creator" metatdata, choose the name of 'creator' as defined in the creatorStrategy property for the field name. Only the last matching value will be retained.
* CONCATENATE\_UNIQUE: choose to concatenate unique string values with a single space separator.
* PICK\_MIN: choose the minimum value and discard all others. If the values are non-numeric, then all non-numeric values will be discarded.
* PICK\_MAX: choose the maximum value and discard all others. If the values are non-numeric, then all non-numeric values will be discarded.

<LwTemplate />

## Configuration

<Tip>
  When entering configuration values in the UI, use *unescaped* characters, such as `\t` for the tab character. When entering configuration values in the API, use *escaped* characters, such as `\\t` for the tab character.
</Tip>

<SchemaParamFields schema={schema} />