how to get all defined scalars

[Diluka]

for example, get all defined scalars as a list from graphql schema files

scalar DateTime
scalar Date
scalar NonNegativeInt

[ardatan]

You can load and merge the type definitions;
https://www.graphql-tools.com/docs/schema-merging#file-loading

Then iterate over the definitions in DocumentNode and filter out scalar type definitions like definition.kind === 'ScalarTypeDefinition'.

Something like below to summarize;

import { loadFilesSync } from '@graphql-tools/load';
import { mergeTypeDefs } from '@graphql-tools/merge';
import { join } from 'path';
import { Kind } from 'graphql';

const scalarTypeNames = new Set<string>();
const typeDefs = mergeTypeDefs(loadFilesSync(join(__dirname, './types')));
for (const definition of typeDefs.definitions) {
  if (definition.kind === Kind.SCALAR_TYPE_DEFINITION) {
     scalarTypeNames.add(definition.name.value);
  }
}

[Diluka]

I can't find document.definitions on loadSchemaSync's return value.

[ardatan]

loadSchemaSync returns GraphQLSchema not DocumentNode. You can iterate over the values of schema.getTypeMap() and filter out the scalars using isScalarType from graphql