valueFromAST.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.valueFromAST = valueFromAST;

var _objectValues3 = _interopRequireDefault(require("../polyfills/objectValues"));

var _keyMap = _interopRequireDefault(require("../jsutils/keyMap"));

var _inspect = _interopRequireDefault(require("../jsutils/inspect"));

var _invariant = _interopRequireDefault(require("../jsutils/invariant"));

var _isInvalid = _interopRequireDefault(require("../jsutils/isInvalid"));

var _kinds = require("../language/kinds");

var _definition = require("../type/definition");

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * Produces a JavaScript value given a GraphQL Value AST.
 *
 * A GraphQL type must be provided, which will be used to interpret different
 * GraphQL Value literals.
 *
 * Returns `undefined` when the value could not be validly coerced according to
 * the provided type.
 *
 * | GraphQL Value        | JSON Value    |
 * | -------------------- | ------------- |
 * | Input Object         | Object        |
 * | List                 | Array         |
 * | Boolean              | Boolean       |
 * | String               | String        |
 * | Int / Float          | Number        |
 * | Enum Value           | Mixed         |
 * | NullValue            | null          |
 *
 */
function valueFromAST(valueNode, type, variables) {
  if (!valueNode) {
    // When there is no node, then there is also no value.
    // Importantly, this is different from returning the value null.
    return;
  }

  if ((0, _definition.isNonNullType)(type)) {
    if (valueNode.kind === _kinds.Kind.NULL) {
      return; // Invalid: intentionally return no value.
    }

    return valueFromAST(valueNode, type.ofType, variables);
  }

  if (valueNode.kind === _kinds.Kind.NULL) {
    // This is explicitly returning the value null.
    return null;
  }

  if (valueNode.kind === _kinds.Kind.VARIABLE) {
    var variableName = valueNode.name.value;

    if (!variables || (0, _isInvalid.default)(variables[variableName])) {
      // No valid return value.
      return;
    }

    var variableValue = variables[variableName];

    if (variableValue === null && (0, _definition.isNonNullType)(type)) {
      return; // Invalid: intentionally return no value.
    } // Note: This does no further checking that this variable is correct.
    // This assumes that this query has been validated and the variable
    // usage here is of the correct type.


    return variableValue;
  }

  if ((0, _definition.isListType)(type)) {
    var itemType = type.ofType;

    if (valueNode.kind === _kinds.Kind.LIST) {
      var coercedValues = [];

      for (var _i2 = 0, _valueNode$values2 = valueNode.values; _i2 < _valueNode$values2.length; _i2++) {
        var itemNode = _valueNode$values2[_i2];

        if (isMissingVariable(itemNode, variables)) {
          // If an array contains a missing variable, it is either coerced to
          // null or if the item type is non-null, it considered invalid.
          if ((0, _definition.isNonNullType)(itemType)) {
            return; // Invalid: intentionally return no value.
          }

          coercedValues.push(null);
        } else {
          var itemValue = valueFromAST(itemNode, itemType, variables);

          if ((0, _isInvalid.default)(itemValue)) {
            return; // Invalid: intentionally return no value.
          }

          coercedValues.push(itemValue);
        }
      }

      return coercedValues;
    }

    var coercedValue = valueFromAST(valueNode, itemType, variables);

    if ((0, _isInvalid.default)(coercedValue)) {
      return; // Invalid: intentionally return no value.
    }

    return [coercedValue];
  }

  if ((0, _definition.isInputObjectType)(type)) {
    if (valueNode.kind !== _kinds.Kind.OBJECT) {
      return; // Invalid: intentionally return no value.
    }

    var coercedObj = Object.create(null);
    var fieldNodes = (0, _keyMap.default)(valueNode.fields, function (field) {
      return field.name.value;
    });

    for (var _i4 = 0, _objectValues2 = (0, _objectValues3.default)(type.getFields()); _i4 < _objectValues2.length; _i4++) {
      var field = _objectValues2[_i4];
      var fieldNode = fieldNodes[field.name];

      if (!fieldNode || isMissingVariable(fieldNode.value, variables)) {
        if (field.defaultValue !== undefined) {
          coercedObj[field.name] = field.defaultValue;
        } else if ((0, _definition.isNonNullType)(field.type)) {
          return; // Invalid: intentionally return no value.
        }

        continue;
      }

      var fieldValue = valueFromAST(fieldNode.value, field.type, variables);

      if ((0, _isInvalid.default)(fieldValue)) {
        return; // Invalid: intentionally return no value.
      }

      coercedObj[field.name] = fieldValue;
    }

    return coercedObj;
  }

  if ((0, _definition.isEnumType)(type)) {
    if (valueNode.kind !== _kinds.Kind.ENUM) {
      return; // Invalid: intentionally return no value.
    }

    var enumValue = type.getValue(valueNode.value);

    if (!enumValue) {
      return; // Invalid: intentionally return no value.
    }

    return enumValue.value;
  }

  /* istanbul ignore else */
  if ((0, _definition.isScalarType)(type)) {
    // Scalars fulfill parsing a literal value via parseLiteral().
    // Invalid values represent a failure to parse correctly, in which case
    // no value is returned.
    var result;

    try {
      result = type.parseLiteral(valueNode, variables);
    } catch (_error) {
      return; // Invalid: intentionally return no value.
    }

    if ((0, _isInvalid.default)(result)) {
      return; // Invalid: intentionally return no value.
    }

    return result;
  } // Not reachable. All possible input types have been considered.


  /* istanbul ignore next */
  (0, _invariant.default)(false, 'Unexpected input type: ' + (0, _inspect.default)(type));
} // Returns true if the provided valueNode is a variable which is not defined
// in the set of variables.


function isMissingVariable(valueNode, variables) {
  return valueNode.kind === _kinds.Kind.VARIABLE && (!variables || (0, _isInvalid.default)(variables[valueNode.name.value]));
}