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// @flow strict
import objectValues from '../polyfills/objectValues';
import type { ObjMap } from '../jsutils/ObjMap';
import keyMap from '../jsutils/keyMap';
import inspect from '../jsutils/inspect';
import invariant from '../jsutils/invariant';
import type { ValueNode } from '../language/ast';
import { Kind } from '../language/kinds';
import type { GraphQLInputType } from '../type/definition';
import {
isLeafType,
isInputObjectType,
isListType,
isNonNullType,
} from '../type/definition';
/**
* 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 |
*
*/
export function valueFromAST(
valueNode: ?ValueNode,
type: GraphQLInputType,
variables?: ?ObjMap<mixed>,
): mixed | void {
if (!valueNode) {
// When there is no node, then there is also no value.
// Importantly, this is different from returning the value null.
return;
}
if (valueNode.kind === Kind.VARIABLE) {
const variableName = valueNode.name.value;
if (variables == null || variables[variableName] === undefined) {
// No valid return value.
return;
}
const variableValue = variables[variableName];
if (variableValue === null && 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 (isNonNullType(type)) {
if (valueNode.kind === Kind.NULL) {
return; // Invalid: intentionally return no value.
}
return valueFromAST(valueNode, type.ofType, variables);
}
if (valueNode.kind === Kind.NULL) {
// This is explicitly returning the value null.
return null;
}
if (isListType(type)) {
const itemType = type.ofType;
if (valueNode.kind === Kind.LIST) {
const coercedValues = [];
for (const itemNode of valueNode.values) {
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 (isNonNullType(itemType)) {
return; // Invalid: intentionally return no value.
}
coercedValues.push(null);
} else {
const itemValue = valueFromAST(itemNode, itemType, variables);
if (itemValue === undefined) {
return; // Invalid: intentionally return no value.
}
coercedValues.push(itemValue);
}
}
return coercedValues;
}
const coercedValue = valueFromAST(valueNode, itemType, variables);
if (coercedValue === undefined) {
return; // Invalid: intentionally return no value.
}
return [coercedValue];
}
if (isInputObjectType(type)) {
if (valueNode.kind !== Kind.OBJECT) {
return; // Invalid: intentionally return no value.
}
const coercedObj = Object.create(null);
const fieldNodes = keyMap(valueNode.fields, (field) => field.name.value);
for (const field of objectValues(type.getFields())) {
const fieldNode = fieldNodes[field.name];
if (!fieldNode || isMissingVariable(fieldNode.value, variables)) {
if (field.defaultValue !== undefined) {
coercedObj[field.name] = field.defaultValue;
} else if (isNonNullType(field.type)) {
return; // Invalid: intentionally return no value.
}
continue;
}
const fieldValue = valueFromAST(fieldNode.value, field.type, variables);
if (fieldValue === undefined) {
return; // Invalid: intentionally return no value.
}
coercedObj[field.name] = fieldValue;
}
return coercedObj;
}
// istanbul ignore else (See: 'https://github.com/graphql/graphql-js/issues/2618')
if (isLeafType(type)) {
// Scalars and Enums fulfill parsing a literal value via parseLiteral().
// Invalid values represent a failure to parse correctly, in which case
// no value is returned.
let result;
try {
result = type.parseLiteral(valueNode, variables);
} catch (_error) {
return; // Invalid: intentionally return no value.
}
if (result === undefined) {
return; // Invalid: intentionally return no value.
}
return result;
}
// istanbul ignore next (Not reachable. All possible input types have been considered)
invariant(false, 'Unexpected input type: ' + inspect((type: empty)));
}
// Returns true if the provided valueNode is a variable which is not defined
// in the set of variables.
function isMissingVariable(
valueNode: ValueNode,
variables: ?ObjMap<mixed>,
): boolean {
return (
valueNode.kind === Kind.VARIABLE &&
(variables == null || variables[valueNode.name.value] === undefined)
);
}
|
