@graphql-tools/merge/esm/typedefs-mergers/fields.js

A set of utils for faster development of GraphQL tools

import { compareNodes } from '@graphql-tools/utils';
import { mergeArguments } from './arguments.js';
import { mergeDirectives } from './directives.js';
import { extractType, isListTypeNode, isNonNullTypeNode, isWrappingTypeNode, printTypeNode, } from './utils.js';
function fieldAlreadyExists(fieldsArr, otherField) {
    const resultIndex = fieldsArr.findIndex(field => field.name.value === otherField.name.value);
    return [resultIndex > -1 ? fieldsArr[resultIndex] : null, resultIndex];
}
export function mergeFields(type, f1, f2, config, directives) {
    const result = [];
    if (f2 != null) {
        result.push(...f2);
    }
    if (f1 != null) {
        for (const field of f1) {
            const [existing, existingIndex] = fieldAlreadyExists(result, field);
            if (existing && !config?.ignoreFieldConflicts) {
                const newField = (config?.onFieldTypeConflict &&
                    config.onFieldTypeConflict(existing, field, type, config?.throwOnConflict)) ||
                    preventConflicts(type, existing, field, config?.throwOnConflict);
                newField.arguments = mergeArguments(field['arguments'] || [], existing['arguments'] || [], config);
                newField.directives = mergeDirectives(field.directives, existing.directives, config, directives);
                newField.description = field.description || existing.description;
                result[existingIndex] = newField;
            }
            else {
                result.push(field);
            }
        }
    }
    if (config && config.sort) {
        result.sort(compareNodes);
    }
    if (config && config.exclusions) {
        const exclusions = config.exclusions;
        return result.filter(field => !exclusions.includes(`${type.name.value}.${field.name.value}`));
    }
    return result;
}
function preventConflicts(type, a, b, ignoreNullability = false) {
    const aType = printTypeNode(a.type);
    const bType = printTypeNode(b.type);
    if (aType !== bType) {
        const t1 = extractType(a.type);
        const t2 = extractType(b.type);
        if (t1.name.value !== t2.name.value) {
            throw new Error(`Field "${b.name.value}" already defined with a different type. Declared as "${t1.name.value}", but you tried to override with "${t2.name.value}"`);
        }
        if (!safeChangeForFieldType(a.type, b.type, !ignoreNullability)) {
            throw new Error(`Field '${type.name.value}.${a.name.value}' changed type from '${aType}' to '${bType}'`);
        }
    }
    if (isNonNullTypeNode(b.type) && !isNonNullTypeNode(a.type)) {
        a.type = b.type;
    }
    return a;
}
function safeChangeForFieldType(oldType, newType, ignoreNullability = false) {
    // both are named
    if (!isWrappingTypeNode(oldType) && !isWrappingTypeNode(newType)) {
        return oldType.toString() === newType.toString();
    }
    // new is non-null
    if (isNonNullTypeNode(newType)) {
        const ofType = isNonNullTypeNode(oldType) ? oldType.type : oldType;
        return safeChangeForFieldType(ofType, newType.type);
    }
    // old is non-null
    if (isNonNullTypeNode(oldType)) {
        return safeChangeForFieldType(newType, oldType, ignoreNullability);
    }
    // old is list
    if (isListTypeNode(oldType)) {
        return ((isListTypeNode(newType) && safeChangeForFieldType(oldType.type, newType.type)) ||
            (isNonNullTypeNode(newType) && safeChangeForFieldType(oldType, newType['type'])));
    }
    return false;
}